chernecky & berger: laboratory tests

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Chernecky & Berger: Laboratory Tests and

Diagnostic Procedures, 5th ed.

Copyright © 2008 Saunders, An Imprint of Elsevier

Chromosome Analysis — Blood Norm.

A total of 46 chromosomes with 22 matched pairs plus XX for females and XY for males.

Usage.

Diagnosis of chromosome abnormalities leading to Down syndrome, ring 20 syndrome(epilepsy), microphthalmia, other physical or mental retardation, and sex chromosome disorders

such as Turner's syndrome or Klinefelter's syndrome; establishes sex in hypogonadism or unclear

genitalia; part of the work-up for amenorrhea, infertility (male and female), frequent

miscarriages, and other chromosome-related disorders and some leukemias and transitional-cellcarcinoma of the bladder; used in genetic counseling for prospective parents and those with a

family history of genetic disease.

Description.

Chromosome analysis involves karyotyping human chromosomes from a culture of leukocytesfrom peripheral blood. Cell replication of the cultured leukocytes is chemically halted in

metaphase, and microscopic photographs are taken of the chromosomes within the cell nucleus.The chromosome pictures are enlarged, and the chromosomes are paired, sorted, and studied for

symmetry of pairs, number of chromosomes, identification of sex chromosomes, and staining patterns.

Professional Considerations

Consent form NOT required.

Preparation

1. See Client and Family Teaching .

2. Preschedule this test with the laboratory.

3. Tube: Green topped.

Procedure

1. Draw a 10-mL blood sample.

Postprocedure Care

1. Write the date and time of specimen collection on the laboratory requisition.

2. Send the specimen to the laboratory immediately and refrigerate until testing. Testing



must occur within 48 hours.

Client and Family Teaching

1. Fast for 3 hours and do not eat fatty foods for 12 hours before specimen collection.

Factors That Affect Results

1. Reject hemolyzed specimens or specimens received more than 24 hours after collection.Other Data

1. Karyotyping may be completed on other tissues including tumor cells, bone marrow,

amniocentesis, or buccal smear.

2. Some forms of leukemia, especially chronic myelogenous, are noted by chromosome

assay of blood.

3. Chromosomal anomalies account for up to 15.7% of male infertility.

4. See also Banding in genetic disorders — Diagnostic .




Follicle-Stimulating Hormone (FSH, Follitropin) — Serum Norm.

Normal ranges will vary among laboratories and are dependent on which international system ofmeasurement is used.

SI Units

Adult Females

LH:FSH Ratio <3:1 <3:1

Premenopausal 3 – 8 mIU/mL 3 – 8 IU/L

Follicular phase 3.85 – 8.78 mIU/mL 3.85 – 8.78 IU/L

Midcycle peak 4.54 – 22.51 4.54 – 22.51 IU/L

Luteal phase 1.79 – 5.12 mIU/mL 1.79 – 5.12 IU/L

Pregnant Low to undetectable

Menopausal 16.74 – 113.59 mIU/mL 16.74 – 113.59 IU/L

Postmenopausal 16.74 – 113.59 mIU/mL 16.74 – 113.59 IU/L

Adult Males 1.27 – 19.26 mIU/mL 1.27 – 19.26 IU/L



2. Repeating the test is often required to ensure an accurate diagnosis.


1. Reject hemolyzed specimens or if the client had a radioactive scan within 48 hours.

2. Radionuclides cause a falsely decreased FSH level.

3. Values should be compared with the norms for the laboratory performing the test.

Other Data

1. Several daily specimens are recommended because of episodic release of FSH from the pituitary gland.

Luteinizing Hormone — Blood Norm.

Ranges vary among laboratories.

SI Units

Adult Females

Follicular phase 5 – 30 mIU/mL 5 – 30 Arb * units

Midcycle 75 – 150 mIU/mL 75 – 150 Arb units

Luteal phase 3 – 40 mIU/mL 3 – 40 Arb units

Postmenopausal 30 – 200 mIU/mL 30 – 200 Arb units

FSH:LH ratio <3.1 <3.1

Adult Males 6 – 23 mIU/mL 6 – 23 Arb units

Female Children

1 – 3 months 7.8 – 27 mIU/mL 7.8 – 27 Arb units

3 – 5 months 5.6 – 20.8 mIU/mL 5.6 – 20.8 Arb units



10 – 13 years 2 – 14 mIU/mL 2 – 14 Arb units


Male Children 1 – 3 months 8.9 – 35.7 mIU/mL 8.9 – 35.7 Arb units







SI Units


Arb means arbitrary.

Usage.

To evaluate infertility in women and men (high serum values of LH are related to gonadaldysfunction, and low values of LH are related to dysfunction or failure of the hypothalamus or

pituitary gland); to evaluate hormonal therapy for inducing ovulation; and to evaluate endocrine

problems related to precocious puberty in children.

Increased.

Amenorrhea, anorchia (congenital absence of testicles), endocrine problems related to precocious puberty in children, hyperpituitarism, Klinefelter's syndrome (in prepubertal boys) (such as sex

chromosome disorder), liver disease, menopause, ovarian or testicular failure (primary gonadaldysfunction), polycystic ovarian disease, primary male hypogonadism, Stein-Leventhalsyndrome (polycystic ovarian disease), tumors (pituitary, testicular), and Turner's syndrome

(ovarian dysgenesis). Drugs include anticonvulsants, clomiphene, naloxone, and spironolactone.

Herbs or natural remedies include Unkei-to.

Decreased.

Adrenal hyperplasia or tumor, amenorrhea (pituitary failure, secondary gonadal insufficiency),

anorexia nervosa, anovulation, hypophysectomy, hypopituitarism, hypothalamic disorder,

luteinizing hormone deficiency, male hypogonadism, malnutrition, ovarian hypofunction

(secondary, tertiary), pituitary disorder, prostate cancer and testicular failure (related to pituitaryfailure). Drugs include atrial natriuretic hormone (long-acting), digoxin, estrogen compounds,

kaliuretic hormone, oral contraceptives, phenothiazines, progesterone, stanozolol, testosterone,

and vessel dilator hormone administration.

Description.

Luteinizing hormone (LH), a glycoprotein, is secreted by the anterior lobe of the pituitary glandin response to stimulation by the hypothalamic release of gonadotropin-releasing hormone. LH

plays a critical role in regulation of ovulatory and reproductive function. In women, LH initiates

luteinization in the ovary, and together with follicle-stimulating hormone (FSH) induces

ovulation. A surge of LH in blood levels indicates that ovulation has occurred. In men, LHstimulates the secretion of androgens and increases the production of testosterone. Together with

FSH, testosterone influences the development and maturation of spermatozoa. Luteinizing

hormone levels peak at midcycle in women of childbearing age, surging when ovulation has

occurred. In menopausal women, levels may be up to five times normal levels.





Preparation

1. Client may be asked to withhold estrogen-containing medications for 4 weeks before the

test.

2. Tube: Red topped, red/gray topped, or gold topped.

3. Document client's age, date of last menstrual period, and whether client is menopausal or premenopausal (females) on laboratory requisition.

4. Discuss with physician whether to withhold medications that could interfere with the test

results.

Procedure

1. In men, one single sample is taken. In women, daily blood samples must be taken at the

same time each day. A series of daily blood specimens can establish the presence or

absence of a midcycle peak in women with anovulatory fertility problems. Alternatively,

several samples may be taken in one day, 20 – 30 minutes apart. This is because LH is

released in a pulsatile manner with levels varying during the menstrual cycle.

2. Draw a 4-mL blood sample without hemolysis.Postprocedure Care

1. None.


1. Encourage the client to express concerns related to infertility or other health problems to

the nurse or the physician.

2. Episodic fluctuations in LH can be great; thus multiple blood samples are more reliablethan a single sample.


1. Hemolysis of the specimen invalidates the results.2. Drugs that could increase or decrease plasma LH levels. (Refer to relevant sections

above.)

3. Women using oral contraceptives will have an absence of midcycle LH peak until the

contraceptives are discontinued.

4. Collection of the daily specimen at different times in the day may cause inaccurate

results.

5. Pulsatile secretion patterns may be disrupted in clients with seizure disorders.

6. Radiology tests involving injection of a radioactive tracer within 7 days before the test

can invalidate the results.Other Data

1. Follicle-stimulating hormone (FSH) level may be requested from the same specimen.

2. Progesterone, not luteinizing hormone, concentration at the time of ovum transfer is a

significant variable associated with spontaneous abortion (miscarriage).






Amniocentesis and Amniotic Fluid Analysis — Diagnostic Routine Analysis

Color: Colorless, straw-colored, or clear to milky-colored.

SI Units

Acetylcholinesterase Negative

Alpha-fetoprotein:

12 weeks of gestation ≤ 42 μg/mL







35 weeks of gestation ≤ 2μg/mL

40 weeks of gestation ≤ 1 μg/mL Normal values may also be reported in multiples of the median (MOM) or 0.5 – 3.0 MOM.

Bilirubin

Trimesters 1 and 2 ≤ 0.074 mg/dL ≤ 1.2 μmol/L

40 weeks of gestation ≤ 0.024 mg/dL ≤ 0.4 μmol/L

Calcium 4 mEq/L 4 mmol/L

Carbon dioxide 16 mEq/L 16 mmol/L

Chloride 102 mEq/L 102 mmol/L

Creatinine

≤27 weeks of gestation 0.8 – 1.1 mg/dL 71 –97 μmol/L

30 – 34 weeks of

gestation

1.1 – 1.8 mg/dL 97 –159 μmol/L

35 – 40 weeks of

gestation

1.8 – 4.0 mg/dL 159 –354 μmol/L



SI Units

Estriol

Trimesters 1 and 2 ≤ 9 μg/dL ≤ 309 nmol/L

Term ≤ 59 μg/dL ≤ 2023 nmol/L

Glucose 30 mg/dL 2 mmol/L

Lecithin

<35 weeks of gestation 6 – 9 mg/dL

≥35 weeks of gestation 15 – 20 mg/dL

Lecithin/sphingomyelin (L/S) ratio

Immaturity ≤ 1:1 <1:1

Borderline maturity 1:1 – 2:1 1:1 – 2:1

Maturity >2:1 >2:1After maturity ≥4:1 ≥4:1

Meconium Negative

Osmolality Equals serum osmolality

pCO2

Trimesters 1 and 2 33 – 55 mm Hg 4.4 – 7.3 kPa

Term 42 – 55 mm Hg 5.6 – 7.3 kPa

pH

Trimesters 1 and 2 7.12 – 7.38 7.12 – 7.38

Term 6.91 – 7.43 6.91 – 7.43

Potassium 4.9 mEq/L 4.9 mmol/L

Protein, total

Trimesters 1 and 2 0.36 – 0.84 g/dL 0.36 – 0.84 g/dL

Term 0.07 – 0.45 g/dL 0.07 – 0.45 g/dL

Sodium 7 – 10 mEq/L lower than serum

sodium

7 – 10 mmol/L lower than serum

sodium

Sphingomyelin 4 – 6 mg/dL

Total protein 2.5 g/dL 25 g/L

Urea

Trimesters 1 and 2 12 – 24 mg/dL 1.2 – 4 mmol/L

Term 19 – 42 mg/dL 3.2 – 7 mmol/L



SI Units

Uric acid

Trimesters 1 and 2 2.76 – 4.68 mg/dL 0.17 – 0.28 mmol/L

Term 7.67 – 12.13 mg/dL 0.46 – 0.72 mmol/L

Abnormalities That May Be Found on Routine Analysis

Abnormal

Color

Possible Cause

Yellow Caused by fetal bilirubin, erythroblastosis fetalis

Green Caused by meconium, breech presentation, fetal death, defecation, distress,

hypoxia, intrauterine growth restriction, status post maturity, vagal stimulation

Red Caused by presence of blood, intrauterine hemorrhage

Port wine Acute fetal distress, abruptio placentaeBrown Oxidized hemoglobin, maternal tissue trauma, fetal death, fetal maceration

SI Units

Abnormal Bilirubin

Fetal involvement 0.10 – 0.28 mg/dL = 1 + 1.6 –4.5 μmol/L

Later fetal involvement 0.29 – 0.36 mg/dL = 2 + 4.7 –5.8 μmol/L

Fetal distress 0.47 – 0.95 mg/dL = 3 + 7.6 –15.4 μmol/L

Fetal death >0.95 mg/dL = 4 + >15.4 μmol/L

SI Units

Abnormal Creatinine

35 – 40 weeks of gestation

Large muscle mass, possible diabetes >4 mg/dL >354 μmol/L

Low birth weight <2 mg/dL <177 μmol/L

Increased Alpha-fetoprotein.

Anencephaly, cleft lip and palate, cystic fibrosis, duodenal atresia, esophageal atresia, fetal

bladder neck obstruction with hydronephrosis, fetal death, meningomyelocele, multiple

pregnancy, nephrosis (congenital), neural tube defects, spina bifida, omphalocele, and Turner'ssyndrome.

Increased Bilirubin.



Anencephaly, erythroblastosis fetalis, hemolytic disease of the newborn, hydrops fetalis,

intestinal obstruction, and Rh sensitization.

Increased Lamellar Bodies in Amniotic Fluid.

Respiratory distress syndrome.

Positive Acetylcholinesterase.

Neural tube abnormalities that allow cerebrospinal fluid (which contains acetylcholinesterase) to

leak into the amniotic sac.

Positive Meconium.

Fetal distress.

Decreased Alpha-fetoprotein.

Not applicable.

Decreased Bilirubin.

Not clinically significant.

Decreased Creatinine.

Fetal lung immaturity.

Chromosome Analysis.

Interpretation required.

Description.

Detection of fetal jeopardy or genetic disease and determination of fetal maturity. Amniocentesisis a 20- to 30-minute procedure in which an aspiration of amniotic fluid is taken

transabdominally and is usually performed after week 12 of gestation. In routine analysis,

amniotic fluid is examined for levels of calcium, chloride, carbon dioxide, creatinine, estriol,

glucose, pH, potassium, sodium, protein, urea, uric acid, and culture and for genetic defects,

chromosomal studies, detection of fetal jeopardy or distress (by color, bilirubin), and to measurelung maturity (by L/S ratio) and age (by creatinine of the fetus). Alpha1-fetoprotein is a globulin

protein secreted by the yolk sac and by fetal liver cells during hepatic cell multiplication. The

highest amounts are found during pregnancy and in hepatic cancer. Measurement is usually performed from week 16 to 20 to help identify fetal neural abnormalities, gastroesophageal

atresia, and nephrosis. Chromosome analysis of amniotic fluid cells is performed by examination

of karyotyped cells for genetic abnormalities such as Down syndrome, Tay-Sachs disease, andother inborn errors of metabolism. Amniotic fluid is examined for color and bilirubin level for



detection of fetal jeopardy or distress caused by hemolysis of fetal red blood cells.

Erythroblastosis fetalis occurs when maternal antibodies attack fetal red blood cells, causing fetal

anemia. This occurs when the mother's blood contains the Rh factor that reacts with fetalerythrocyte antigens. The test is usually performed at gestation week 24 or later and can help

determine the need for intrauterine fetal blood transfusion. After the 35th week of pregnancy, the

phospholipid levels of lecithin and sphingomyelin change in a predictable pattern that indicatesthe level of maturity of fetal lungs. Lecithin rises and sphingomyelin decreases as the fetal lungsmature.


Consent form IS required.

Risks

Bleeding, intrauterine death, premature labor, spontaneous abortion.

Contraindications

Abruptio placentae, incompetent cervix, placenta previa, and a history of premature labor.

Preparation

1. Obtain an amniocentesis tray, surgical scrub solution, a light-protected container, and

povidone-iodine solution. Also obtain RhoGAM for Rh-negative mothers.

2. Obtain maternal vital signs. Auscultate baseline fetal heart tones.

3. Note the estimated date of conception and week of gestation on the laboratory

requisition.

4. Procedure should be performed in a darkened room if the specimen will be tested for bilirubin.


6. Just before beginning the procedure, take a ―time out‖ to verify the correct client, procedure, and site.

Procedure

1. The position of the fetus and a pocket of amniotic fluid are determined using ultrasoundand palpation, with the mother in a supine position.

2. The mother's abdominal area is cleansed with surgical scrub solution and povidone-

iodine and allowed to dry.

3. The aspiration site is draped to demarcate a sterile field.

4. The mother is instructed to place her hands behind her head, and the aspiration site is

anesthetized with 1 mL of 1% or 2% lidocaine intradermally and subcutaneously.

5. A 20- to 22-gauge, 5-inch-long spinal needle with a stylet is inserted through the

abdominal wall into the intrauterine cavity, and the stylet is withdrawn.



6. About 7 – 15 mL of amniotic fluid is aspirated through the spinal needle into a syringe,

and the needle is withdrawn. Use a 20-mL amniotic fluid sample for direct genetic

analysis for the four most common mutations responsible for Tay-Sachs disease.

Postprocedure Care

1. Apply a dry, sterile dressing to the aspiration site.

2. Inject 2 – 5 mL of amniotic fluid into a light-protected (foil-covered or amber) test tube to

test for bilirubin. Inject 5 – 10 mL of amniotic fluid into a sterile, siliconized glasscontainer or a polystyrene container for culture and genetic and other studies (AFP).

Specimens to be transported to another site for testing should be packed in a cool,

insulated container to maintain a temperature of 2 – 5 degrees C. Freezing temperaturesshould be avoided.

3. Obtain the mother's vital signs. Auscultate fetal heart tones for changes from the baseline

value.

4. The mother should rest on her right side for 15 – 20 minutes after the procedure.

5. RhoGAM may be prescribed for Rh-negative mothers.

6. Transport the amniotic fluid specimen to the laboratory immediately and refrigerate.


1. Empty your bladder immediately before the procedure if gestation is 21 weeks or more.

You must have a full bladder during the procedure if gestation is 20 weeks or less.

2. It is important to lie motionless throughout the procedure. You may experience a strongcontraction with the needle insertion.

3. Chromosome analysis results may take up to 4 weeks.

4. After the procedure, notify the physician for cramping, abdominal pain, unusual vaginal

drainage/fluid loss, fever, chills, dizziness, or more or less than the usual amount of fetalactivity.

5. Inform the client with abnormal genetic findings of choices regarding pregnancy and pregnancy termination. Also refer the client for genetic counseling before future attempts

to become pregnant.


1. Reject frozen or clotted specimens.

2. Inadvertent aspiration of maternal urine can be ruled out by testing the specimen for

blood urea nitrogen (BUN) and creatinine. Urine BUN is >100 mg/dL, whereas amniotic

fluid is well under 100 mg/dL. Urine creatinine is usually >80 mg/dL, whereas amnioticfluid creatinine is usually ≤4 mg/dL.

3. Nonsiliconized glass containers for routine analysis may result in cell adherence on the

sides of the container.

4. Amniotic fluid testing must be performed within 3 days of collection.

5. Amniocentesis should be performed between weeks 24 and 28 when one is checking for

hemolytic disease of the newborn and Rh sensitization.



6. Falsely low bilirubin levels may result from failure to protect the specimen from light.

7. Specimens contaminated with blood should be tested for fetal hemoglobin to determine

whether the blood is of maternal or fetal origin. Fetal blood contamination results infalsely high bilirubin levels. Fetal or maternal blood will interfere with measurements of

fetal lung maturity and amniotic fluid constituents that are also constituents of plasma,

such as protein, potassium, and glucose.

8. Creatinine levels are affected by maternal creatinine clearance and maternal creatinine

levels. A concurrent maternal serum creatinine should be drawn. Maternal serum to

amniotic fluid creatinine ratio should be about 2:1.

9. Elevated AFP results may be caused by contamination of the specimen with fetal blood.

10. Small and closed neural tube defects may not cause elevated AFP levels.

11. Accurate L/S ratio measurement is not possible if the specimen is contaminated with

blood (fetal or maternal) or meconium.

Other Data

1. Direct karyotyping of placental villi samples obtained by needle aspiration has been

found to yield faster results than amniotic fluid chromosome analysis. (See Chorionic

villi sampling — Diagnostic .)

2. Chromosomal aberration has been found in 4.6% of fetuses in women >38 years of age,

the most common being trisomy 21 (62%), Klinefelter's syndrome (11%), and Edward'ssyndrome (trisomy 18) (11%).

3. For diamniotic twin pregnancies, each amniotic sac should be sampled.

4. Early amniocentesis is feasible from 11 weeks of gestation and can be performed for the

usual indications as an alternative to chorionic villus sampling. Results are available in

less than 1 week using cytogenetic techniques.5. Prenatal cystic fibrosis profile may be performed by polymerase chain reaction (PCR) for

mutations (F508, R553X, g551D, g542X, n1303K, and w1282X).

6. Amniotic fluid neuron-specific enolase is useful as a marker for neonatal neurologic

injury.

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Oral Cavity Cytology — Specimen Norm.



Negative.

Usage.

Cancers of the tongue, gum, or mouth; Candida albicans; herpesvirus infection; human immune

deficiency virus; Klinefelter's syndrome; pemphigus; trisomy 13, 18, and 21; and Turner'ssyndrome.

Description.

Microscopic examination of cells scraped from the oral cavity surface.



Preparation

1. Obtain a glass of water, a spatula or tongue blade, a glass slide, a specimen container of

95% ethyl alcohol (ethanol) or spray fixative, and a light source.

2. Label the slide with the client's name and the specimen source.

Procedure

1. The client should rinse the mouth vigorously with water several times before the scraping

is performed.

2. The lesion or oral surface is scraped with a spatula or tongue blade.

3. Smear the scraping on a labeled glass slide and fix it immediately in 95% alcohol or

spray fixative.

Postprocedure Care

1. The requisition should include age; physical findings; history of smoking, dentures, skin

lesions, and reverse smoking; and history of chemotherapy, immunotherapy, or radiation

therapy.


1. Results are normally available in 24 – 48 hours.


1. Failure to fix specimens invalidates the results.

Other Data

1. Occasional diagnosis of palatal salivary gland neoplasm occurs.






Thyroid Function Tests — Blood Norm.

SI Units

Free ThyroxineIndex

Mean

Puberty throughadulthood

4.2 – 13.0 8.0

Cord blood 6.0 – 13.2 9.8

First 72 hours 9.9 – 17.5 13.9

7 days 7.5 – 15.1 11.2

4 – 52 weeks 5.0 – 13.0 8.4

1 – 3 years 5.4 – 12.5 8.13 – 10 years 5.7 – 12.8 8.2

Thyroxine (T4) Radioimmunoassay

Adults 4.5 –12.0 μg/dL 58.5 – 155 nmol/L

Pregnant >14 weeks 9.1 –14.0 μg/dL 117 – 181 nmol/L

Elderly (>60 years)

Female 5.5 –10.5 μg/dL 71 – 135 nmol/L

Male 5.0 –10.0 μg/dL 65 – 129 nmol/L

Children

Cord blood 7.4 –13.0 μg/dL 95 – 168 nmol/L

First 72 hours 11.8 –22.6 μg/dL 152 – 292 nmol/L

7 – 14 days 9.8 –16.6 μg/dL 126 – 214 nmol/L

4 – 16 weeks 7.2 –14.4 μg/dL 93 – 186 nmol/L

4 – 12 months 7.8 –16.5 μg/dL 101 – 213 nmol/L

12 months-5 years 7.3 –15.0 μg/dL 94 – 194 nmol/L

5 – 10 years 6.4 –13.3 μg/dL 83 – 172 nmol/L

10 – 15 years 5.6 –11.7 μg/dL 72 – 151 nmol/L

Triiodothyronine (T3) Radioimmunoassay

Adults 80 – 230 ng/dL 1.2 – 3.5 nmol/L

Children

Cord blood 15 – 75 ng/dL 0.23 – 1.16 nmol/L



SI Units

First 72 hours 32 – 216 ng/dL 0.49 – 3.33 nmol/L

7 – 14 days Average 250 ng/dL Average 3.85 nmol/L

2 – 4 weeks 160 – 240 ng/dL 2.46 – 3.70 nmol/L

4 – 16 weeks 117 – 209 ng/dL 1.80 – 3.22 nmol/L

16 – 52 weeks 110 – 280 ng/dL 1.70 – 4.31 nmol/L

1 – 5 years 105 – 269 ng/dL 1.62 – 4.14 nmol/L

5 – 10 years 94 – 241 ng/dL 1.45 – 3.71 nmol/L

10 – 15 years 83 – 213 ng/dL 1.28 – 3.28 nmol/L

Thyroid-Stimulating Hormone (TSH)

Adults 0.4 –4.7 μU/mL 0.4 – 4.7 mU/L

>60 yearsFemale 2.0 –16.8 μU/mL 2.0 – 16.8 mU/L

Male 2.0 –7.3 μU/mL 2.0 – 7.3 mU/L

Newborn (1 – 3 days) 3.0 –20.0 μU/mL 3.0 – 20.0 mU/L

Premature Infant 0.5 –29.0 μU/mL 0.5 – 29.0 mU/L

Thyroglobulin (Tg) Undetectable (NOTE: Tg is only measured after total thyroid ablation todetect recurrent thyroid cancer.)

Usage.

Work-up of suspected thyroid disorder and differentiation of primary thyroid disease fromsecondary causes and from abnormalities in thyroid-binding globulin levels.

Description.

Thyroid function testing involves performing several measurements on one sample of blood.These tests have largely been replaced by the third-generation thyroid-stimulating hormone

assay. Tests included are as follows: Thyroid test: Free thyroxine index — Serum; Thyroid test:

Thyroid-stimulating hormone — Blood and sensitive assay; Thyroid test: Thyroxine — Blood; andThyroid test: Triiodothyronine — Blood. See individual test listings for further description. Many

clients are found to have subclinical thyroid disease as described below, which may or may not be treated. Subclinical hypothyroidism is more common than subclinical hyperthyroidism.

SUBCLINICAL THYROID DISEASE FINDINGS

Imaging Findings Sensitive

TSH

Thyroxine Triiodothyronine

Subclinical Asymptomatic Suppressed Normal Normal



Imaging Findings Sensitive

TSH

Thyroxine Triiodothyronine

hyperthyroidism abnormalities

Subclinical

hypothyroidism

Asymptomatic

abnormalities

Mildly

elevated

Normal

CONDITIONS CAUSING CHANGES IN THYROID FUNCTION TESTS

Low Free T3 or Free T4 Normal Free T3 or

Free T4

High Free T3 or Free T4

High

TSH Endogenous Causes Endogenous Causes Endogenous Causes

Amyloid goiter

Iodine organificationdefect

Iodine transportabnormalitiesRiedel's thyroiditis

Thyroglobulin synthetic

defectThyroid dysgenesis

Thyroiditis (chronic

autoimmune)

Thyroiditis (transient,hypothyroid phase)

TSH-receptor defects

TSH-resistanceTTF2 mutations

Pendred's syndrome

Heterophile antibodySubclinical

autoimmunehypothyroidismState of recovering

from non-thyroid

illnessTSH receptor defects

TSH-resistance

Anti-TPO antibodies

FamilialDysalbuminemic

hyperthyroxinemiaPituitary tumor that secretes TSHPsychiatric illness (acute)

Thyroid hormone resistance

Exogenous Causes Exogenous Causes Exogenous Causes

Amiodarone therapyLithium therapy

Interferon therapy

Interleukin therapy Afterradioiodine treatment

After neck radiation

therapy

Iodine deficiency Iodine-excess goiter Post

thyroidectomy

Amiodarone therapyCholestyramine

therapy

Intermittent T4 therapy

Sertraline therapy

Amiodarone therapyIntermittent T4 therapy

Normal

TSH

Same as above

Low

TSH

Endogenous Causes Endogenous Causes Endogenous Causes



Low Free T3 or Free T4 Normal Free T3 or

Free T4

High Free T3 or Free T4

Congenital deficiencyHypothyroidism

(secondary)

Nonthyroidal illnessTSH suppression

secondary to recent

treatment for

hyperthyroidism

Hyperthyroidism(subclinical)

Nonthyroidal illness

Exogenous Causes Thyroxine ingestion

Dobutamine therapy

Dopamine therapy

Steroid therapy

Activating germline TSH-receptormutation

Graves' disease

Hydatidiform moleHyperthyroidism (primary)

Iodine excess *

Multinodular goiter

Pregnancy: thyrotoxicosis withhyperemesis gravidarum or

familial gestational

hyperthyroidism

Presence of ectopic thyroid tissue*

Thyroiditis (lymphocytic) *

Thyroiditis (postpartum) *Thyroiditis (postviral) *

Thyroiditis (transient) *

Toxic nodule

Exogenous Causes Amiodarone therapy *

Thyroxine ingestion *

Modified from Dayan CM: Interpretation of thyroid function tests, Lancet 357(9256): 619 – 624,

2001 (review).

Accompanied by low radioiodine uptake.



Preparation

1. Tube: Red topped, red/gray topped, or gold topped.

Procedure

1. Completely fill the tube with venous blood.

Postprocedure Care 1. None.


1. Results are normally available within a few days.


1. Results are invalidated if the client has undergone a radionuclide scan within 7 days

before the test.



2. Abnormal thyroid test findings often found in critically ill clients should be repeated after

the critical nature of the condition is resolved.

3. The production, circulation, and disposal of thyroid hormone are altered throughout thestages of pregnancy

4. An herb or botanical that may interfere with success of thyroid replacement therapy iskelp, which contains iodine.

Other Data

1. Many illness affect thyroid test values, but are not indicative of thyroid disease. For this

reason, routine thyroid testing of hospitalized clients is not recommended.

2. An herbal or natural remedy that interferes with thyroid medication is kelp.


Diagnostic Procedures, 5th ed. Copyright © 2008 Saunders, An Imprint of Elsevier

Bone Radiography — Diagnostic Norm.

Negative.

Usage.

Identification of abnormal growth patterns by serial radiography. Detection of ankylosingspondylitis, congenital abnormalities, fractures, healing fractures, hyperparathyroidism,

infection, joint destruction, osteomalacia, osteomyelitis, osteoporosis, the presence of joint fluid,

rickets, and tumors.

Description.

Specific bones are radiographed in several positions for visualization of the bone from all angles.Kiru et al (2002) found magnetic resonance imaging superior to bone radiography for detecting

bone stress injuries in the early phase of damage.



Precautions

During pregnancy, risks of cumulative radiation exposure to the fetus from this and other previous or future imaging studies must be weighed against the benefits of the procedure.



Although formal limits for client exposure are relative to this risk-benefit comparison, theUnited States Nuclear Regulatory Commission requires that the cumulative dose equivalent to

an embryo/ fetus from occupational exposure not exceed 0.5 rem (5 mSv). Radiation dose to

the fetus is proportional to the distance of the anatomy studied from the abdomen anddecreases as pregnancy progresses. For pregnant clients, consult the radiologist/radiology

department to obtain estimated fetal radiation exposure from this procedure.Preparation

1. Handle injured parts carefully.

2. Shield the client's testes, ovaries, or pregnant abdomen.

Procedure

1. The client is placed on the radiography table in several positions, with a radiograph taken

in each position.

2. The client must lie still for the radiograph.

Postprocedure Care

1. The client remains in the radiology department until it is determined that the films aresatisfactory.


1. The amount of exposure to radiation is minimal and not dangerous.

2. It is important to stay still during the radiograph.

3. Results are normally available within 24 hours.


1. Movement results in an unsatisfactory radiograph.

2. Too little or too much exposure results in a radiograph that is too light or too dark and

may need to be repeated for interpretation.

Other Data

1. Wear a lead apron if remaining in the room with the client during radiography.





Glucose Tolerance Test (GTT) — Blood Norm (Serum Levels).

Intravenous GTT SI Units



hydrochloride, indomethacin, isoniazid, levodopa, levothyroxine sodium, lithium carbonate,

magnesium hydroxide (prolonged high doses), mercaptopurine, methimazole, methyldopa,

methyldopate hydrochloride), nalidixic acid, nicotine, nicotinic acid, oral contraceptives,oxazepam, p-aminosalicylic acid, phenolphthalein, phenytoin, phenytoin sodium, progestins,

promethazine hydrochloride, propranolol (in diabetic clients), propylthiouracil, reserpine,

ritodrine hydrochloride, terbutaline sulfate, tetracyclines, thiazides, thyroglobulin, thyroid,tolbutamide (SMA methodology), and triamterene.

Decreased Results (Increased Glucose Tolerance).

Addison's disease (oral GTT only), celiac disease (oral GTT only), hepatic disease,

hypoglycemia, hypoparathyroidism (oral GTT only), hypothyroidism (oral GTT only), islet cell

adenoma, malabsorption (oral GTT only), narcotic addiction, pancreatic islet cell hyperplasia,

and sprue (oral GTT only). Drugs include allopurinol, amphetamines, beta-adrenergic blockers,caffeine, chlorpropamide, clofibrate, edetate disodium, ethyl alcohol (ethanol), guanethidine

sulfate, isoniazid, insulin, isocarboxazid, marijuana, nitrazepam, oral hypoglycemic agents, p-

aminosalicyclic acid, pargyline hydrochloride, phenacetin, phenazopyridine, phenelzine sulfate, phenformin, propranolol (in diabetic clients), and tranylcypromine sulfate.

Description.

Glucose is a monosaccharide formed from the digestion of carbohydrates and the conversion of

glycogen by the liver and is the body's main source of cellular energy. The glucose tolerance test

is most commonly used to aid in the diagnosis of diabetes mellitus. If blood glucose levels peakat higher than normal levels at 1 and 2 hours (after injection or ingestion of glucose) and are

slower than normal to return to fasting levels, diabetes mellitus is confirmed.



Preparation


2. Tubes: Gray topped × 6 – 7.

3. Label each tube as shown in the table below (See Procedure 4).

Procedure

1. Begin the test between 7 and 9 AM.

2. Draw a 1 – 4-mL venous blood sample.

3. Intravenous GTT: Inject a standardized intravenous solution of 0.5 g/kg of body weight

of 50% glucose, or 50 mL of 50% glucose intravenously over 4 minutes.

4. Oral GTT: Adults should completely ingest a solution containing 75 – 100 g of glucosewithin 5 minutes.

Tube Number Intravenous GTT Oral GTT



1 Fasting Fasting

2 5 minutes 30 minutes

3 30 minutes 1 hour

4 1 hour 1.5 hours

5 2 hours 2 hours

6 3 hours 3 hours

7 4 hours 4 hours

For children, the dosages are as follows:

<18 months: 2.5 g/kg

18 months-3 years: 2.0 g/kg

3 years-12 years: 1.75 g/kg

>12 years: 1.25 g/kg (100-g limit)

5. Repeat step 2 at the following precise time intervals after infusion or ingestion of glucose

is started.

6. If evaluating for postprandial hypoglycemia, draw an additional sample at 4 hours.

Postprocedure Care

1. Current administration of medications known to affect the test results should be noted on

the laboratory requisition.

2. Send blood samples to the laboratory immediately or refrigerate them.Client and Family Teaching

1. Eat a high-carbohydrate (200 – 300 g) diet for 3 days before testing.

2. Avoid alcohol, coffee, and smoking for 36 hours before testing.

3. Fast (except for water) for 10 – 16 hours.

4. When possible, drugs affecting results should be stopped 3 – 21 days before the test.

5. Insulin and oral hypoglycemic agents should be withheld the morning of the test.

6. Avoid strenuous exercise for 8 hours before and after the test.

7. Because the test requires multiple blood samples, suggest bringing a book or other quietdiversion to the test because it usually requires a minimum of 3 hours.

8. Alert the client to the symptoms of hypoglycemia and instruct the client to report these

symptoms immediately.


1. No eating, smoking, or exercise is permitted during the testing period. Caffeine interfereswith the accuracy of the results.



2. Water may be given to help ease the collection of urine specimens.

3. Failure to adhere to a high-carbohydrate diet for 3 days before the test may produce

abnormally increased results.

4. Stresses caused by acute illness, pregnancy, or surgery invalidate the results.

5. Slight increases are normal in clients more than 50 years of age (up to 1 mg/dL per yearfor ages more than 50 years).

6. When the glucose oxidase/peroxidase procedure is used, falsely decreased glucose values

may occur when the client has recently taken acetaminophen or oxycodone.

Other Data

1. This test usually takes 3 – 5 hours.

2. 10 mL of urine for glucose measurement may also be collected at the same time as the

blood samples.

3. The intravenous glucose tolerance testing method is recommended for clients who may

have impaired or erratic intestinal absorption of glucose.

4. The oral glucose tolerance test has been shown to be unreliable for use in the evaluation

of reactive hypoglycemia.

5. In a client with non – insulin-dependent diabetes (type 1), fasting serum glucose levels

may be within normal range, but insufficient secretion of insulin after ingestion of

carbohydrates causes serum glucose to increase sharply and return to normal slowly.

6. If a client develops severe hypoglycemia during the test, draw a blood sample, record the

time on the laboratory requisition, and discontinue the test. Have the client ingest an oral

form of glucose or administer intravenous glucose according to the physician's orders.

7. A 2-hour glucose level is better than a fasting level alone in identifying older adults atincreased risk of major incident cardiovascular events (Smith et al, 2002).

8. A 2-hour glucose ≥11.1 mmol/L increases risk for pr eterm delivery.




Glucose — Blood Norm.

Dependent on time and content of last meal. In normal clients, glucose levels return to the fastinglevel (given in these norms) within 2 hours after the last meal.



SI Units

Whole Blood

Adults 60 – 89 mg/dL 3.3 – 4.9 mmol/L

>60 years 68 – 98 mg/dL 3.8 – 5.4 mmol/L

Children

Cord blood 38 – 82 mg/dL 2.1 – 4.6 mmol/L

Premature infant 17 – 51 mg/dL 0.9 – 2.8 mmol/L

Neonate 25 – 51 mg/dL 1.4 – 2.8 mmol/L

Newborn to 24 hours 34 – 51 mg/dL 1.9 – 2.8 mmol/L

Newborn >24 hours 42 – 68 mg/dL 2.3 – 3.8 mmol/L

Child 51 – 85 mg/dL 2.8 – 4.7 mmol/L

Serum Adults 65 – 100 mg/dL 3.6 – 5.5 mmol/L

>60 years 80 – 115 mg/dL 4.4 – 6.4 mmol/L

Children

Cord blood 45 – 96 mg/dL 2.5 – 5.3 mmol/L

Premature infants 20 – 60 mg/dL 1.1 – 3.3 mmol/L

Neonates 30 – 60 mg/dL 1.7 – 3.3 mmol/L

Newborn to 24 hours 40 – 60 mg/dL 2.2 – 3.3 mmol/L

Newborn >24 hours 50 – 80 mg/dL 2.8 – 4.4 mmol/L

Child 60 – 100 mg/dL 3.3 – 5.5 mmol/L

NOTE: Whole-blood glucose values are about 15% less than serum glucose values because ofgreater dilution.

Panic Levels

Adults <40 mg/dL or >700 mg/dL <2.2 mmol/L or >38.6 mmol/L

Neonates <30 mg/dL or >300 mg/dL <1.6 mmol/L >16.0 mmol/L

Panic Level Symptoms and Treatment — Increased Symptoms.

Abdominal pain, fatigue, muscle cramps, nausea, polyuria, thirst, and vomiting.

Treatment



NOTE: Treatment choice(s) depend(s) on client's history and condition and episode history.

1. Administer subcutaneous or intravenous injection of insulin per sliding scale.Intravenous insulin is typically administered by continuous infusion for panic levels

accompanied by reduced level of consciousness. Hourly adjustments are based onsubsequent blood glucose measurements.

2. Perform hourly neurologic checks.

3. Monitor hourly intake and output.

4. Monitor for hypokalemia as side effect of treatment.

Panic Level Symptoms and Treatment — Decreased Symptoms.

Confusion, headache, hunger, irritability, nervousness, restlessness, sweating, and weakness.

Treatment

NOTE: Treatment choice(s) depend(s) on client's history and condition and episode history.

1. Administer oral form of glucose followed by oral ingestion of carbohydrates. Forneonates or unconscious clients, give IV glucose or IV/IM glucagon.

Increased.

Acromegaly, anesthesia, burns, carbon monoxide poisoning, cerebrovascular accident,

convulsions, Cushing's disease, Cushing's syndrome, cystic fibrosis, diabetes mellitus, eclampsia,

encephalitis, erectile dysfunction, gigantism, hemochromatosis, hemorrhage, hyperosmolarhyperglycemic nonketotic coma (HHNK), hyperthyroidism, hyperpituitarism, hyperadrenalism,

hypertension, hypervitaminosis A (chronic), infections, injury, malnutrition (chronic),

meningitis, myocardial infarction, obesity, pancreatic carcinoma, pancreatic insufficiency, pancreatitis (chronic), pheochromocytoma, pituitary adenoma, pregnancy, shock, subarachnoid

hemorrhage, stress, trauma, and Wernicke's encephalopathy. Drugs include anabolic steroids,

androgens, arginine, ascorbic acid, asparaginase, aspirin, atenolol, baclofen, benzodiazepines, bisacodyl (prolonged use), chlorpromazine, chlorthalidone, cimetidine, clonidine,

corticosteroids, corticotropin, dextran, dextrothyroxine, diazoxide, disopyramide phosphate,

epinephrine, epinephrine bitartrate, epinephrine borate, epinephrine hydrochloride, estrogens,

ethacrynic acid, furosemide, glucose infusions, haloperidol, imipramine, isoproterenol

hydrochloride, heparin calcium, heparin sodium, hydralazine hydrochloride,hydrochlorothiazide, indomethacin, isoniazid, levodopa, levothyroxine sodium/T4, lithium

carbonate, magnesium hydroxide (prolonged high doses), meperidine, mercaptopurine,

methimazole, methyldopa, methyldopate (hydrochloride), metronidazole, nalidixic acid, niacin,nicotine, nicotinic acid, oral contraceptives, oxazepam, p-aminosalicyclic acid, phenolphthalein,

phenytoin, phenytoin sodium, progestins, promethazine hydrochloride, propranolol (in diabetic

clients), propylthiouracil, protease inhibitors, reserpine, rifampin, risperidone, ritodrine



hydrochloride, sildenafil, terbutaline sulfate, tetracyclines, thiazides/thiazide diuretics,

thyroglobulin, thyroid medications, tolbutamide (SMA methodology), and triamterene.

Decreased.

Addison's disease, adrenal medulla unresponsiveness, alcoholism, carcinoma (adrenal gland,stomach, fibrosarcoma), cirrhosis, cretinism, diabetes mellitus (early), dumping syndrome,

exercise, fever, Forbes' disease (type III glycogen deposition disease), fructose intolerance,

galactosemia, glucagon deficiency, hepatic phosphorylase deficiency (type VI glycogen storagedisease), hepatitis, hyperinsulinemia, hypopituitarism, hypothermia, hypothyroidism, infant of

diabetic mother, insulin overdose (factitious hypoglycemia), insulinoma, kwashiorkor, leucine

sensitivity, malnutrition, maple syrup urine disease, muscle phosphofructokinase deficiency

(type VII glycogen storage disease), myxedema, pancreatic islet cell tumor, pancreatitis,

postoperatively (after gastrectomy or gastroenterostomy), postprandial hypoglycemia, Reye'ssyndrome, Simmonds' disease, vomiting, von Gierke's disease (type I glycogen storage disease),

Waterhouse-Friderichsen syndrome, and Zetterstrom syndrome. Drugs include acetaminophen,

allopurinol, amphetamines, aspirin, atenolol, beta-adrenergic blockers, caffeine, cerivastatin,chlorpropamide, clofibrate, edetate disodium, ethyl alcohol (ethanol), gatifloxacin, guanethidine

sulfate, isoniazid, insulin, isocarboxazid, marijuana, nitrazepam, oral hypoglycemic agents, p-

aminosalicylic acid, pargyline hydrochloride, phenacetin, phenazopyridine, phenelzine sulfate, phenformin, propranolol (in diabetics), tetracyclines, theophylline, and tranylcypromine sulfate.

Herbs or natural remedies include zhi mu (‗know-mother,' Anemarrhena asphodeloides, an herb)

and shi gao (‗stone-plaster,' calcium sulfate, gypsum) taken in combination; xuan shen (‗blackginseng,' Scrophularia ningpoensis, figwort) and cang zhu (‗green- shu/zhu herb,' Atractylodeslancea, var. ovata) taken in combination; shan yao (‗mountain-medicine,' Dioscorea batatas,

potato yam) and huang qi (‗yellow-old 60,' Astragalus reflexistipulus, or A. hoantchy, yellow

vetch) taken in combination; and karela ( Momordica charantia, balsam apple) taken incombination with chlorpropamide. Herbs or natural remedies include teas (decoctions, infusions)

containing chromium, karela, ginseng, guar gum, meshasringi (Gymnema sylvestre, mesha

shringi, Indian milkweed vine), methi (fenugreek leaves), syzigium cumini (jamun), tundika

(Coccinia indica).

Description.

Glucose is a monosaccharide found naturally occurring in fruits. It is also formed from thedigestion of carbohydrates and the conversion of glycogen by the liver and is the body's main

source of cellular energy. Glucose is essential for brain and erythrocyte function. Excess glucose

is stored as glycogen in the liver and muscle cells. Hormones influencing glucose metabolism

include insulin, glucagon, thyroxine, somatostatin, cortisol, and epinephrine. Fasting glucose

levels are used to help diagnose diabetes mellitus and hypoglycemia. A randomly timed test forglucose is usually performed for routine screening and nonspecific evaluation of carbohydrate

metabolism. The American Diabetes Association criteria for diagnosis of diabetes mellitusinclude a fasting plasma glucose level of >126 mg/dL (7 mmol/L).



chernecky & berger: laboratory tests

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