chapter 19 blood chemistry and serology. elsevier items and derived items © 2008 by saunders, an...

CHAPTER 19CHAPTER 19BLOOD CHEMISTRY AND SEROLOGY

Elsevier items and derived items © 2008 by Saunders, an imprint of Elsevier Inc. 2

PRETESTPRETEST

True or False1. Most of the cholesterol found in the blood comes

from the intake of dietary cholesterol.

2. The primary use of the cholesterol test is to screen for the presence of coronary heart disease.

3. LDL picks up cholesterol from ingested fats and the liver and carries it to the cells.

4. The function of glucose in the body is to build and repair tissue.

5. Insulin is required for normal utilization of glucose in the body.


PRETEST, CONT.PRETEST, CONT.

True or False6. An abnormally low level of glucose in the body is

known as hypoglycemia.

7. The hemoglobin A1C test measures the average amount of blood glucose over a 3-month period.

8. An antibody is a substance that is capable of combining with an antigen.

9. Mononucleosis is transmitted through coughing and sneezing.

10. Blood antigens (A, B, Rh) are located on the surface of red blood cells.


Content OutlineContent Outline

1. Automated blood analyzers: designed for use in medical office

a. Perform blood chemistry tests in a short period of time

b. Operating manual includes:• Operation

• Test parameters

• Care and maintenance

Introduction to Blood Chemistry and Serology


Blood ChemistryBlood Chemistry

1. Chemicals are dissolved in liquid part of blood

2. Quantitative measurement of chemical substances in blood

a. Quantitative test: indicates the exact amount of a substance that is present


Blood Chemistry, cont. Blood Chemistry, cont.

3. Serum specimen usually required for blood chemistry tests

4. Type of test ordered: depends on clinical diagnosis


Automated Blood Chemistry Analyzers

Automated Blood Chemistry Analyzers

1. Reflectance photometer: measures light intensity to determine amount of substance present

a. Provides a quantitative measurement of chemical substances or analytes present

2. Examples of blood chemistry analyzers

a. ATAC laboratory system

b. Reflotron Analyzer


Automated Blood Chemistry Analyzers, cont.

Automated Blood Chemistry Analyzers, cont.

3. Operating manual explains how to:

a. Collect and handle specimen

b. Perform quality control procedures

c. Test specimen

(Personnel available for on-site training)


Quality ControlQuality Control

1. Quality control: consists of methods and means to ensure that test results are reliable and valid

a. Calibration of the analyzer

b. Running controls

2. Calibration: the use of a standard to check precision of the blood chemistry analyzer

a. If analyzer not properly calibrated: unable to produce accurate results


Quality Control, cont. Quality Control, cont.

3. Control: consists of a sample with a known value

a. Processed in same way as patient specimen

b. Results should fall within a specified range:• Indicated on reference sheet that comes with

control



c. Types of controls:

• Normal control: results fall within normal range

• Abnormal control: results fall outside of normal range

– Low abnormal: below normal range

– High abnormal: above normal range



d. If control does not fall within specified range may be caused by:• Problems or errors with analyzer

• Problem with technique used to perform test

• Problem with chemical reagents

– Consult operating manual



4. CLIA requirement: for moderate complexity testsa. Calibration: at least every 6 months

b. Two levels of controls: daily• Example: Running a normal and high control

c. When problems or errors are identified:• Must document action to correct them

d. Medical office running CLIA-waived tests• Required to follow manufacturer’s instructions

- Include quality control procedures that must be performed


CholesterolCholesterol

1. White, waxy, fatlike substance (lipid)2. Essential for normal functioning of

body

a. Important component of cell membranes

b. Used in production of:• Hormones

• Bile


Cholesterol, cont. Cholesterol, cont.

3. Cholesterol in the blood:

a. Most manufactured by liver

b. Portion comes from individual's diet: dietary cholesterol• Found only in animal products (organ meats,

egg yolks, dairy products)



4. Cholesterol level determined by:

a. Genetic makeup

b. Amount of dietary cholesterol and saturated fat consumed



5. High cholesterol: excessive amount of cholesterol in blood

a. May cause atherosclerosis

• Atherosclerosis: buildup of fatty deposits (plaque) on the walls of the arteries

• As progresses: arteries become more occluded

– Can lead to heart attack or stroke



b. High blood cholesterol: risk factor for coronary heart disease (CHD)• Efforts should be made to lower cholesterol

level


HDL and LDL CholesterolHDL and LDL Cholesterol

1. Cholesterol transported in blood as a complex molecule known as a lipoprotein

a. Lipoprotein: A complex molecule consisting of protein and a lipid fraction such as cholesterol• Lipoproteins function in transporting lipids in

the blood


HDL and LDL Cholesterol, cont. HDL and LDL Cholesterol, cont.

2. Two types of lipoproteins:

a. LDL: low-density lipoprotein

b. HDL: high-density lipoprotein



3. LDL

a. Picks up cholesterol from ingested fats and the liver• Delivers it to blood vessels and muscles where

it is deposited in cells



b. Often referred to as "bad cholesterol"• Excess causes plaque to build up on the

arterial walls (atherosclerosis)

– Risk factor for CHD



4. HDL

a. Removes excess cholesterol from cells• Carries it to liver to be excreted

b. Protective and beneficial to the body



c. Often called "good cholesterol"

d. High HDL cholesterol level: reduces risk of CHD

e. Below 40 mg/dL: risk factor for CHD


Cholesterol TestingCholesterol Testing

1. Adults over age 20:

a. Should have a cholesterol test every 5 years

2. Initial testing includes:

a. Total cholesterol determination• Combined measurement of LDL and HDL

cholesterol


Cholesterol Testing, cont. Cholesterol Testing, cont.

3. Most physicians also order HDL determination

a. Measures only HDL cholesterol in the blood

4. Elevated results: usually require confirmation through further testing

a. Before diagnosis of high blood cholesterol can be made


Interpretation of ResultsInterpretation of Results

1. Total cholesterol

a. Desirable: Below 200 mg/dL

b. Borderline high: 200 to 239 mg/dL

c. High: 240 mg/dL or higher


Interpretation of Results, cont.Interpretation of Results, cont.

2. High category: increased risk for CHD

3. Borderline high category: at increased risk if other risk factors present

a. Example: overweight, smoker


Interpretation of Results, cont. Interpretation of Results, cont.

4. HDL Cholesterol

a. Optimal: 60 mg/dL or above

b. Desirable: 45 to 59 mg/dL

c. Borderline low: 40 to 45 mg/dL

d. Increased risk for CHD: Below 40 mg/dL


Patient PreparationPatient Preparation

1. Total cholesterol and HDL cholesterol:

a. Fasting not usually required


Patient Preparation, cont Patient Preparation, cont

2. If total cholesterol level is 200 mg/dL or higher: lipid profile usually ordered

a. Lipid profile includes:• Total cholesterol

• HDL cholesterol

• LDL cholesterol

• Triglycerides


Patient Preparation, cont. Patient Preparation, cont.

b. Triglycerides affected by food consumption• Patient must fast

– For at least 12 hours before test

• Fasting: Abstaining from food or fluids (except water) for a specified amount of time before the collection of a specimen



3. Interpretation of Test Results

a. Triglycerides• Normal: Below 150 mg/dL

• Borderline high: 150 to 199 mg/dL

• High: 200 to 499 mg/dL

• Very high: 500 mg/dL or higher

• Increased risk for CHD: Over 150 mg/dL



b. LDL Cholesterol• Optimal: Below 100 mg/dL

• Near optimal: 100 to 129 mg/dL

• Borderline high: 130 to 159 mg/dL

• High: 160 to 189 mg/dL

• Very high: 190 mg/dL or higher


What Would You Do?What Would You Not Do?



Blood Urea NitrogenBlood Urea Nitrogen

1. Blood urea nitrogen (BUN): kidney function test

2. Urea: end product of protein metabolism

a. Normally present in blood

3. Kidney disease: may cause abnormal increase in BUN


Blood GlucoseBlood Glucose

1. Glucose: end product of carbohydrate metabolism

2. Function of glucose: chief source of energy for body

a. Energy needed to:• Carry out normal body functioning

• Maintain body temperature


Blood Glucose, cont. Blood Glucose, cont.

3. Glucose can be stored as glycogen for later use in:

a. Muscle tissue

b. Liver tissue glycogen in muscle and liver tissue for later use

4. When no more tissue space available to store glycogen:

a. Glucose is converted to fat and stored as adipose tissue



5. Insulin

a. Hormone secreted by beta cells of pancreas

b. Required for normal utilization of glucose

c. Enables glucose to enter cells and be converted to energy

d. Also needed for proper storage of glycogen in liver and muscle cells



6. Blood Glucose Testing

a. Glucose measurement used to detect:• Diabetes mellitus

• Hypoglycemia

• Liver and adrenocortical dysfunction



7. Testing methods

a. Fasting blood sugar (FBS)

b. 2-hour postprandial glucose test (PPBS)

c. Glucose tolerance test (GTT)


Fasting Blood SugarFasting Blood Sugar

1. FBS: patient must be fasting

a. No food or fluid (except water) for 12 hours before test


Fasting Blood Sugar, cont. Fasting Blood Sugar, cont.

2. Medications that may affect test:

a. Oral contraceptives

b. Salicylates

c. Diuretics

d. Steroids



3. Physician may restrict medications before testing

4. Test should be scheduled in the morning

a. Minimizes patient inconvenience due to fasting

5. FBS normal range: 70 to 110 mg/dL



6. Purpose of FBS

a. Evaluate progress of diabetic patients

b. Regulate treatment of diabetic patients

c. Routine screening procedure to detect diabetes



7. FBS above 120 mg/dL: dividing point between normal and hyperglycemic values

a. Indicative of diabetes mellitus

8. Elevated FBS: further testing required (e.g., GTT)


Two-Hour Postprandial Blood Sugar

Two-Hour Postprandial Blood Sugar

1. Purpose

a. Screen for presence of diabetes

b. Monitor effects of insulin dosage in diagnosed diabetes


Two-Hour Postprandial Blood Sugar, cont.


2. Fasting required: beginning at midnight until breakfast

a. Breakfast: Patient consumes a prescribed meal containing 100 grams of carbohydrates • Alternative: drink 100 grams of glucose

solution

3. Blood specimen collected 2 hours after consumption

4. Nondiabetic patient: glucose returns to normal within 1½ to 2 hours




5. Diabetic patient: does not return to fasting level

6. 140 g/dL or higher: suggestive of diabetes

a. Warrants further testing


Glucose Tolerance Test (GTT)Glucose Tolerance Test (GTT)

1. Provides more detailed information on glucose utilization

a. Assesses insulin response to glucose load

2. Used to diagnose:

a. Diabetes mellitus

b. Hypoglycemia

c. Liver and adrenocortical dysfunction


Glucose Tolerance Test (GTT), cont.


3. Testing Requirements

a. High carbohydrate diet for 3 days before test (150 grams)

b. Fasting




4. Testing procedure

a. FBS performed and urine is tested for glucose• If FBS indicates hyperglycemia: notify

physician

– Hyperglycemia contraindicates administering the glucose solution

b. After FBS: patient drinks measured amount of glucose (100 grams)




c. Blood and urine specimens collected at intervals: 30, 60, 120, and 180 minutes

d. Label blood and urine specimens with exact time of collection




e. Restrictions during test• No eating or drinking except water: affects

glucose level

– Encourage water: easier to produce urine specimen

• No smoking: stimulant that increases blood glucose level

• Remain at test site: so patient is present for specimen collection

• Minimize activity: activity uses glucose

– Affects test results




5. Side Effects

a. Patient may exhibit normal side effects during the test• Weakness

• Feeling of faintness

• Perspiration

– Reassure patient that it is only temporary




b. Serious symptoms: immediately report to physician• Indicate severe hypoglycemia

– Headache

– Pale

– Cold and clammy skin

– Irrational speech or behavior

– Profuse perspiration

– Fainting




6. Interpretation of Results

a. Nondiabetic patient after ingestion of glucose solution• Glucose absorbed into bloodstream

• Rises to a peak level: between 160 and 180 mg/dL

– Approximately 30 to 60 minutes after consumption of glucose solution




• Pancreas secretes insulin to compensate for rise

• Blood glucose returns to fasting level within 2 to 3 hours

• Urine is negative for glucose




b. Diabetic patient after ingestion of glucose solution • Blood glucose level peaks at a much higher

level

• Glucose present in urine

• Blood glucose levels above normal throughout test

– Due to lack of insulin




7. Hypoglycemia

a. Blood glucose is abnormally low

b. During GTT patients exhibits low level • Beginning at 2-

hour interval

• Continues up to 4 to 5 hours




c. Hypoglycemia results from:• Glucose removed from blood at an excessive

rate

• Decreased secretion of glucose into blood




d. Hypogylcemia can be caused by:• Overdose of insulin

• Addison's disease

• Bacterial sepsis

• Pancreatic cancer

• Hepatic necrosis

• Hypothyroidism




e. GTT not required if:• FBS is above 140 mg/dL

• 2-hour PPBS is above 180 mg/dL

– Results greater than these amounts: qualify for diabetes diagnosis


Tests for Management of Diabetes

Tests for Management of Diabetes

1. Important for diabetic patients to manage their condition

a. Best accomplished: keeping blood glucose levels close to normal• Patient experiences fewer symptoms

• Delays or prevents long-term complications

– Leads to a longer life


Tests for Management of Diabetes, cont.


2. Types of tests

a. Self-monitoring of blood glucose• Performed by patient at

home

• Measures day-day fluctuations in blood glucose level




b. Hemoglobin A1C test• Ordered by physician

• Provides overall picture of blood glucose level over a period of time


Self-Monitoring of Blood Glucose (SMBG)

Self-Monitoring of Blood Glucose (SMBG)

1. Diabetic patients: usually cannot tell by the way they feel

a. Whether blood glucose is within normal range

b. Only way to know for sure: SMBG• Provides patient with feedback for maintaining

normal blood glucose level

• Assists in anticipating and treating fluctuations in blood glucose caused by:


Self-Monitoring of Blood Glucose (SMBG), cont.


• Assists in anticipating and treating fluctuations in blood glucose caused by:

– Food

– Exercise

– Stress

– Infection




2. Insulin-dependent diabetic patients:

a. Must monitor glucose at home for effective management• Based on results: decisions can be made

regarding insulin and dietary adjustments

– To maintain normal blood glucose levels

• Avoids extremes of hypoglycemia and hyperglycemia




• Reduces symptoms of the disease

• Helps delay or prevent long-term complications

– Examples: Retinopathy, peripheral vascular disease




3. Frequency of Testing

a. Depends on:• Severity of the diabetes

• Diet

• Presence of special conditions (e.g., pregnancy)

• Activity level




b. Insulin-dependent diabetic patient:• Ideally should monitor four times a day

– In the morning: after an 8-hour fast (best overall indicator of control)

– Before lunch

– Before dinner

– Bedtime

• Before lunch, dinner, and at bedtime: provide guidance for adjusting insulin dosage, diet, and exercise




4. Test Results

a. Blood glucose levels• Measured using a glucose

meter

– Results displayed in mg/dL (milligrams per deciliter)




b. Diabetic patients: should keep a record of daily glucose test results• For periodic review by the physician

– Assists physician in making decisions regarding diabetic management plan




5. Advantages of SMBG:

a. Most effective way to maintain normal blood glucose level • High blood glucose for a long period of time

(above 180 mg/dL)

– Causes progressive damage to body organs leading to:

1) Blindness

2) Kidney disease

3) Nerve damage

4) Circulation problems




b. Convenience of testing• No physician order

required

• Can test any time of day

• Can test when side effect occurs (e.g., hypoglycemia)

– Treatment can be instituted immediately




c. More involvement in self-management decisions• Insulin dosage, meal planning, physical

activity




d. Reliable decisions can be made regarding insulin dosage• During situations that affect blood glucose

level:

– Illness

– Emotional stress

– Increased physical activity

– Suspected hypoglycemia




e. Prevent or delay in long-term complications• Increases chance of staying healthy


Hemoglobin A1C Test (Hb A1C)Hemoglobin A1C Test (Hb A1C)

1. Assessment of average amount of glucose in the blood: over a 3-month period

2. Food consumed containing glucose

a. Glucose absorbed into circulation


Hemoglobin A1C Test (Hb A1C), cont.


b. Glucose has sticky quality• Sticks to protein making up hemoglobin

(glycosylation)

• Hemoglobin: found in red blood cells (RBCs)

– Function: transports oxygen to tissues of body




c. Glycosylation: the process of glucose attaching to hgb• Occurs in all individuals

– Both diabetic and normal

• Forms a compound: hemoglobin A1C




d. Amount of glucose that attaches to hgb: • Proportional to amount of glucose in an

individual's blood

e. Undiagnosed or poorly controlled diabetic patients• Have a higher than normal blood glucose level

• More Hb A1C forms in these patients




1. Hb A1C test: measures the percentage of Hb A1C

a. Attachment of glucose to hemoglobin: permanent for life of RBC (90 to 120 days)

b. Provides overall picture of blood glucose for the past 3 months




2. Interpretation of Results

a. Normal individuals: 4% to 6%

b. Diabetic individuals:• Recommendation: Less than 7%

– Better chance of delaying or preventing diabetic complications

• If higher than 8%: change in diabetic management plan required




3. Testing recommendations

a. When patient is first diagnosed with diabetes

b. Several times after management plan has been prescribed for a newly diagnosed patient• To verify blood glucose control is being

achieved




c. For diagnosed diabetic patients: to evaluate effectiveness of mgt plan• Stable diabetic patients under good control:

At least 2 times a year (every 6 months)

• Patients who have difficulty maintaining control: Test ordered more frequently

d. After physician makes an adjustment to diabetic management plan• To assess effectiveness of change in

treatment


Glucose MetersGlucose Meters

1. Quantitatively measures blood glucose


Glucose Meters, cont. Glucose Meters, cont.

2. On-site testing

a. Provides immediate results• Physician can make decisions regarding:

– Diagnosis

– Treatment

– Follow-up care



3. Reagent Test Strips

a. Plastic strip with a reaction pad• Pad contains

chemicals: react with glucose in blood



b. Results displayed as a digital readout in mg/dL



c. Storage: cool, dry area at room temperature with cap tightly closed: • Chemicals on strip: sensitive to heat, light,

and moisture

• Causes deterioration of chemicals

– Leads to inaccurate test results



d. Strips that are discolored or have darkened: discard• To prevent inaccurate test results

e. Container includes desiccant• Absorbs moisture to promote dryness



3. Care and Maintenance of Glucose Meter

a. Handle carefully• Physical jar could result in malfunction

b. Do not place in high humidity area (e.g., bathroom)



c. Do not expose to severe variations in environmental temperature• Example: Leaving in a vehicle on a hot/cold

day



d. Clean meter properly• Exterior of meter:

– Use a soft, clean cloth dampened with mild cleaning agent

– Dry thoroughly

• Do not let water run into glucose meter

– Could damage internal components



e. Replace battery• Screen displays alert of low battery

– Directions for installation: specified in operator's manual



4. Calibration Procedures

a. Purpose of calibration:• Ensures the glucose meter is functioning

properly

• Ensures accurate and reliable test results

– Programs the electronics of the glucose meter to match reactivity of strips in current use (compensates for variables in the manufacturing process of the reagent strip)


Calibrating the MeterCalibrating the Meter



5. Control Procedure

a. Ensures:• Test results are reliable and valid

• Errors are eliminated

b. Commercially available glucose control solutions • Use two of the following levels of controls

– High

– Low



c. Control solution • Effective for 3 months from date opened

• After opening: write date on label

• Can be used for (whichever comes first):

– 3 months from date opened

– Expiration date stamped on label

• Store control in cool, dry area at room temperature

-Solution is sensitive to heat, light, moisture


Glucose Meters, cont.Glucose Meters, cont.

d. If control results not within acceptable range:• Check expiration date of test strips and control

solution

• Make sure test strips were stored at room temperature

• Make sure code on meter matches code on test strips

• Review technique used to run control procedure

– Correct any errors and run control again

– If still not in acceptable range: contact manufacturer



e. Should be performed• Daily, before using meter for first time

• When new container of reagent strips is opened

• If cap left off vial of strips for a length of time

– If meter is dropped

– If test has been repeated and result is lower or higher than expected


SerologySerology

1. Study of the serum of the blood

a. Specifically deals with the study of antigen and antibody reactions

2. Antigen: a substance capable of stimulating the formation of antibodies

a. Examples: Bacteria, viruses, bacterial toxins, allergens, blood antigens

3. Antibody: a substance capable of combining with an antigen

a. Results in an antigen-antibody reaction


Serology, cont. Serology, cont.

4. Use of serology tests

a. Assess the presence of a substance• Example: ABO blood typing

b. Diagnosis of disease• Example: Mononucleosis testing

• Follow the course of a disease


Serologic TestsSerologic Tests

1. Hepatitis Test: detection of viral hepatitis

a. Five types of viral hepatitis: A, B, C, D, E

b. Determines specific type of hepatitis


Serologic Tests, cont. Serologic Tests, cont.

2. Syphilis Test

a. Sexually transmitted disease caused by Treponema pallidum

b. Screening tests most commonly used• VDRL (Venereal Disease Research Laboratory)

• RPR (Rapid Plasma Reagin)



c. Syphilis results reported as:• Nonreactive: negative

• Weakly reactive: positive

• Reactive: positive

d. Positive result warrants more specific testing



3. Mononucleosis (mono) Test

a. Detects presence of infectious mononucleosis

4. Rheumatoid Factor (RF)

a. Rheumatoid arthritis (RA): chronic inflammatory disease that affects joints

b. Blood of individual with RA: contains rheumatoid factor (RF)

c. Test detects presence of RF antibodies• Assists in diagnosis of rheumatoid arthritis



5. Antistreptolysin O test

a. Detects ASO antibodies

b. Used to detect conditions resulting from strep infections and secondary strep infections:• Rheumatic fever

• Glomerulonephritis

• Bacterial endocarditis

• Scarlet fever



6. C-Reactive Protein (CRP)

a. CRP appears in blood: during inflammation and tissue destruction

b. Used to diagnose and determine progress of:• Rheumatoid arthritis

• Acute rheumatic fever

• Widespread malignancy

• Bacterial infections



7. Cold Agglutinins

a. Detect presence of cold agglutinin antibodies

b. Cold agglutinins found in patients with:• Infectious mononucleosis

• Mycoplasmal pneumonia

• Chronic parasitic infections

• Lymphoma



8. ABO and Rh Blood Typing

a. Determines ABO and Rh blood type

b. Purpose• Prevent blood transfusion or transplant

reactions

• Identify problems (e.g., hemolytic disease of newborn)



9. Rh Antibody Titer

a. Determines amount of Rh antibodies in the blood

b. Can occur in a pregnant woman • Rh-negative woman carrying Rh-positive fetus

• Most frequent use of test:

– Detect Rh incompatibility problem with a mother and an unborn child


Rapid Mononucleosis TestingRapid Mononucleosis Testing

1. Infectious mononucleosis: acute infectious disease caused by Epstein-Barr virus (EBV)

a. Most frequently affects children and young adults

b. Transmitted: saliva by direct oral contact • Often called "kissing disease"


Rapid Mononucleosis Testing, cont.


c. Symptoms• Mental and physical fatigue

• Fever

• Sore throat

• Severe weakness

• Headache

• Swollen lymph nodes




2. Rapid mononucleosis test: often performed in medical office

a. Assists in diagnose of infectious mononucleosis

3. Individuals with mononucleosis: produce heterophile antibody

a. Usually by sixth to tenth day of the illness

b. Test detects this antibody




4. A positive mononucleosis test and patient symptoms

a. Basis for diagnosis of infectious mononucleosis


Blood TypingBlood Typing

1. Each individual has a blood type

a. Depends on antigens on the surface of RBCs

• Blood antigen: A protein present on the surface of RBCs that determines a person's blood type

– Inherited through genes

– Programs the body to produce a particular antigen

Blood Antigens


Blood Antigens, cont.Blood Antigens, cont.

2. Blood antigens: Grouped into categories known as blood group systems

3. ABO and Rh blood group systems:

a. Most likely to cause problems in:• Blood transfusions

• Rh disease of newborn

b. Most commonly tested for in medical laboratory


Blood Antigens, cont.Blood Antigens, cont.

4. ABO blood group system:

a. Type A blood: A antigen present

b. Type B blood: B antigen present

c. Type AB blood: A and B antigens present

d. Type O blood: Neither A or B antigen is present


ABO Blood AntigensABO Blood Antigens


Blood AntibodiesBlood Antibodies

1. Blood antibody: A protein present in the plasma that is capable of combining with its corresponding blood antigen

a. To produce an antigen-antibody reaction


Blood Antibodies, cont. Blood Antibodies, cont.

2. Body never produces an antibody to combine with its own blood antigen

a. Example: If blood type is A: Plasma does not contain the A antibody• B antibody naturally occurs in this patient's

plasma

• B antibody cannot combine with A antigen



3. If a blood antigen and its corresponding antigen combine:

a. A serious antigen-antibody reaction takes place



4. Antibodies present

a. Type A blood: B antibody

b. Type B blood: A antibody

c. Type AB blood: Neither A or B antibody

d. Type O blood: Both A and B antibodies


The Rh Blood Group SystemThe Rh Blood Group System

1. Discovered by Landsteiner and Weiner

a. While working with rhesus monkeys (1940)

2. Rh-positive: Have Rh antigen present on the surface of RBCs

a. Most of population is Rh-positive


The Rh Blood Group System, cont.

The Rh Blood Group System, cont.

3. Rh-negative

a. 15% of white population do not have Rh antigen

b. 7% of black population do not have Rh antigen


Blood Antigen and Antibody Reactions

Blood Antigen and Antibody Reactions

1. When blood antigen and its corresponding antibody unitea. Results in clumping of RBCs: known as

agglutination

b. Can be serious or fatal if occurs in the living body (in vivo)

c. Clumped RBCs cannot pass through small tubules of kidneys• Results in kidney failure

d. Eventually leads to hemolysis2. Can occur if wrong blood type

administered during transfusion


Agglutination and Blood Typing

Agglutination and Blood Typing

1. Agglutination of RBCs: basis for ABO and Rh blood typing

a. Antigen-antibody reaction occurs in vitro


Agglutination and Blood Typing, cont.

Agglutination and Blood Typing, cont.

2. To perform blood typing:

a. Commercially prepared antiserum used• Antiserum: a serum containing antibodies

b. Added to an unknown blood specimen

c. Example: Antiserum with A antibody added to unknown blood specimen• If A antigen present: combines with A

antibody

– Results in agglutination: indicates type A blood


Antigen Antibody ReactionAntigen Antibody Reaction


POSTTESTPOSTTEST

True or False1. Serum is required for most blood chemistry tests.2. The buildup of plaque (due to high cholesterol) on

the walls of arteries is known as thrombophlebitis.3. An HDL cholesterol level greater than 50 mg/dL is

a risk factor for coronary heart disease.4. The triglyceride test requires that the patient not

eat or drink for 12 hours before the test.5. The normal range for a fasting blood sugar is 120

to 160 mg/dL.


POSTTEST, CONT.POSTTEST, CONT.

True or False6. The glucose tolerance test is used to assist in the

diagnosis of diabetes mellitus.7. Before meals, it is recommended that the blood

glucose level for a diabetic patient fall between 60 to 80 mg/dL.

8. The recommended A1C level for an individual with diabetes is 4 % to 6%.

9. The RPR test is a screening test for syphilis.10. The varicella virus causes infectious

mononucleosis

chapter 19 blood chemistry and serology. elsevier items and derived items © 2008 by saunders, an...

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