urinalysis- methods, observations and clinical significance

Urinalysis - Methods, Observations and Interpretations

(Macroscopic Analysis)

By- Professor(Dr.) Namrata ChhabraBiochemistry for medics- Lecture Notes

http://www.namrata.co/category/about-the-author/

http://www.namrata.co/

Introduction

• Urine is an excretory product of the body

• It is formed in the kidney

• Urine examination helps in the diagnosis of various renal as well as systemic diseases

04/12/23 2Biochemistry for medics- Lecture Notes

Specimen collection

• For most of the routine investigations fresh mid stream specimen of 10-20 ml urine is collected in a clean dry vial

• In some cases 24 hour urine sample is also collected


Sample preservation

• There is no single all purpose preservative• For determination of urea, ammonia, nitrogen and

calcium- Hydrochloric acid is used (2 N or concentrated HCL)

• For determination of sodium, potassium, chloride, bicarbonate, calcium, phosphorus, urea, ammonia, amino acids, creatinine, proteins, reducing substances and ketone bodies- Thymol is used

• For determination of Ascorbic acid- Acetic acid is used• Toluene is a very satisfactory preservative for urine


Composition of normal urine

Composition depends on Kidney functions• Glomerular filtration• Tubular reabsorption and•Tubular secretion


Composition of normal urine

• Normal urine contains 90-95 % water and about 60 G/day of solid constituents which may be organic or inorganic in nature

04/12/23 Biochemistry for medics- Lecture Notes 6

Organic constituents of urine

S.No. Constituent Concentration (G/day)

1. Urea 25-30

2. Uric acid 0.5-0.8

3. Creatinine 1-1.8

4. Hippuric acid 0.7-0.8


Inorganic constituents of urine

S.No. Constituent Concentration (G/day)

1 Chlorides 10-152 Sodium 3-53 Potassium 2-2.54 Calcium 0.1-0.35 Phosphates 0.8-1.36 Sulphates 1.0-1.27 Ammonia 0.7-0.804/12/23 8Biochemistry for medics- Lecture Notes

Physical Examination of urine

I) Colour- Freshly excreted urine is colorless to straw colored

• The normal color of urine is due to the presence of pigment urochrome

• Trances of other substances, such as- Uroerythrin, urobilin, uroporphyrin and coproporphyrins also contribute to the color of urine


Variations in urinary color

S.No. Color Interpretation

1 Dark yellow

• Concentrated urine- Mild dehydration• Vitamin B complex therapy

2 Orange Drug induced

3 Pinkish Excessive beet root intake

A) Physiological Variations


Variations in urinary colorB) Pathological Variations

S.No. Color Interpretation

1 Deep yellow Jaundice

2 Reddish Haematuria

3 Brownish Hemoglobinuria, myoglobinuria and porphyrias

4 Brown to black Alkaptonuria

5 Cloudy Pus cells and bacteria in infected cells

6 Smoky Red blood cells

7 Black Iron therapy

8 Pinkish brown Presence of urobilin – Hemolytic anemias

9 Milky white Chyluria(Presence of fat globules)04/12/23 11Biochemistry for medics- Lecture Notes

Variations in urinary color



II) Volume of urine- Normal volume-800-2,500 ml/day with an average of 1500 ml/day. Approximately 500 ml/day is the minimum volume of urine needed in normal health to remove waste products The volume of urine is affected by-•Fluid intake•Fluid loss•Type of diet•Cardio-vascular status and•Renal functions


Variations in volume of urine excreted

A) Polyuria- Polyuria implies an increased volume of urine excreted per day, generally volume of urine exceeding 2,500 ml/day is termed as Polyuria.Conditions causing Polyuria• Diabetes mellitus• Diabetes Insipidus• Late stage of chronic glomerulonephritis•Drug induced- Diuretics• Alcohol• Compulsive polydipsia



B) Oliguria- Volume of urine less than 500 ml/day is termed oliguria.

Conditions causing oliguria• Fever• Diarrhea (loss of fluid from extra renal sites)• Severe edema• Acute nephritis• Early stage of acute glomerulonephritis• Cardiac failure and hypertension (reduced

circulatory volume)



C) Anuria- Complete cessation of urine or volume of excreted urine less than 100 ml/day.

Conditions causing Anuria• Acute tubular necrosis• Blood transfusion reaction• Surgical shock• Bilateral renal stones• Sulphonamide therapy



III) Specific Gravity- The specific gravity indicates the concentrating ability of the kidneys.In normal health the urinary specific gravity ranges between 1.016-1.025, the average being 1.020. The specific gravity is affected by-• Volume of urine excreted and• The amount of solids present in the urine


Variations in specific gravity of urine

A) Low specific gravity- 1.016 or lessConditions• Compulsive polydipsia• Diabetes Insipidus• Glomerulonephritis• Pyelonephritis


Variations in specific gravity of urine

B) High specific gravity of urine- 1.025 or moreConditions causing high specific gravity of urine• Severe dehydration• Nephrotic syndrome (Due to proteinuria)• Diabetes mellitus ( Due to glycosuria)• Adrenal insufficiency(Excess of sodium in urine)• Congestive heart failure• Hepatic diseases• Extra renal water losses (fever, vomiting and

diarrhea)04/12/23 19Biochemistry for medics- Lecture Notes

Variations in specific gravity of urineFixed specific gravity (Isosthenuria)• Fixed specific gravity is seen in chronic renal

failure.• Specific gravity of urine is based on tubular

function• In the late stages of chronic renal failure,

kidneys fail to concentrate or dilute urine, which has a constant specific gravity ranging between 1.008-1.012(average 1.010) same as that of plasma.


Measurement of specific gravity

• The specific gravity is measured by Urinometer• The instrument floats in the urine• The calibration mark that corresponds to the surface

level of urine is read• It is calibrated at 15o C, temperature correction is

done by adding 0.001 for every 3 degree above 15o C or subtracting 0.001 for every 3 degree below15o C .

• Proteinuria increases specific gravity, 0.003 is subtracted for every G/L of urinary protein


Measurement of specific gravity

Urinometer04/12/23 22Biochemistry for medics- Lecture Notes


IV- Odor of urine• Normal urine has an aromatic odor• Variations• Ammoniacal Odor- On keeping sample for a

long time• Acetone like Odor- Ketonuria such as Diabetic

ketoacidosis or starvation• Foul smell due to bacterial infections


Physical Examination of urineV) pHNormal urine is acidic, pH ranges between 4.5-8.0 with

a mean of 6.0 in 24 hoursVariations of urinary pHA)Acidic urine- Physiologically, It is found after• A protein rich diet• Heavy exercisePathologically , It is found in conditions of acidosis,

such as diabetic ketoacidosis, respiratory acidosis, and high fever (break down of tissue proteins)



Variations of urinary pHB) Alkaline pHPhysiologically it is found after• Heavy meals• Diet rich in citrus fruits• Excessive intake of milk and antacidsPathologically, it is found in-• Urinary tract infections• Conditions of alkalosis


Measurement of urinary pH

Urinary pH is measured by-

• pH papers• Litmus papers


Analysis of normal constituents

A) Inorganic constituentsi) Test for Urinary chlorides(silver nitrate test)Principle- Silver chloride is precipitated in the

presence of nitric acid and silver nitrate. Procedure-Take 2 ml of urine and add 0.5 ml of

concentrated nitric acid and 1 ml of silver nitrate. A white precipitate of silver chloride appears.


i) Test for urinary chlorides

Interpretation: a) Increased Urinary chlorides:

Polydipsia, use of diuretics and Addison's disease.

b) Decreased urinary chlorides: Excessive sweating, fasting, diarrhea, excessive vomiting, edema, diabetes Insipidus, infections and adrenocortical hyper function (Cushing's syndrome).


ii) Test for urinary sulphates

Barium chloride test (test for sulphates)

Principle: Urinary sulphate is precipitated as barium sulphate on reaction with barium chloride solution.

Procedure: Take 3 ml of urine and add 1 ml of conc. HCl and 2 ml of 10% barium chloride. White precipitate indicates the presence of sulphates.


ii) Test for urinary sulphates

Interpretationa) Increased urinary sulphate: Cystinuria,

Homocystinuria, melanuria, obstructive jaundice, hepatocellular jaundice, cyanide poisoning and high protein diet .

b) Decreases urinary sulphates are observed in conditions of renal functional impairment.


iii) Test for Urinary phosphatesAmmonium molybdate test (Test for Urinary phosphates)Principle: Upon warming with ammonium molybdate in the presence of nitric acid, inorganic phosphates are precipitated as canary yellow ammonium phospho molybdate.Procedure: To 3 ml of urine, add a few drops of concentrated nitric acid and a pinch of ammonium molybdate. Warm it. Observe the yellow color of the precipitate.


iii) Test for Urinary phosphatesInterpretation: a) Increased urinary phosphates: Rickets,

osteomalacia, hyperparathyroidism, acidosis. b) Decreased urinary phosphates: Diarrhea,

nephritis, parathyroid hypofunction, pregnancy, hereditary fructose intolerance and galactosemia.


IV) Test for Urinary Calcium

Potassium oxalate test (Test for urinary calcium)Principle: With potassium oxalate in acidic medium, calcium is precipitated as calcium oxalate. Procedure: To 2 ml of urine, add 5 drops of 1% acetic acid and 5 ml of potassium oxalate. White precipitate of calcium oxalate is formed.


IV) Test for Urinary CalciumInterpretation: Increased urinary calcium: • Hyperparathyroidism,• Hyperthyroidism, • Hypervitaminosis D, • Multiple myeloma, • Renal stones• Renal tubular acidosis, • Steroids and diuretic therapy04/12/23 34Biochemistry for medics- Lecture Notes

V) Test for Ammonia

Principle: Ammonia is evaporated when urine is made alkaline. Urinary ammonia is derived from glutamine and other amino acids. Procedure: To 5 ml of urine add; add 2% sodium carbonate till the solution is alkaline to litmus. Boil the solution. Place a piece of moistened red litmus paper at the mouth of the test tube. Note the change in color to blue due to evolution of ammonia.


V) Test for Ammonia

Interpretation: a) Increased urinary ammonia:

Diabetic keto acidosis, ingestion of acid forming foods, excessive water ingestion, urinary tract infections.

b) Decreased urinary ammonia: Alkalosis, nephritis.

Damp red litmus paper turns blue on exposure to fumes of ammonia.


B) Tests for Organic Constituents

1) Test for Urea (Sodium hypobromite test)Principle: When urea is treated

with sodium hypobromite, it decomposes to give nitrogen.

Procedure: To 2 ml of urine in a test tube, add 4-5 drops of sodium hypobromite. Observe the effervescence of nitrogen gas. 04/12/23 37Biochemistry for medics- Lecture Notes


Urease test for ureaPrinciple: Soyabean powder contains the

enzyme urease. This enzyme under pH 7-8 and temperature 550C decomposes urea in to ammonia and carbon dioxide which together form ammonium carbonate (alkaline component) which changes the slightly acidic reaction(yellow color) to alkaline reaction(pink color).



Biuret test for ureaPrinciple : Urea when heated decomposes with

the liberation of ammonia and the formation of biuret. Biuret is dissolved in water and develops a violet color forming a complex with alkaline copper sulphate solution.


i) Tests for Urea

Interpretation: a) Increased urinary urea: Fever, diabetes

mellitus, excess of adrenocortical activity b) Decreased urinary urea: Liver diseases,

metabolic or respiratory acidosis, nephritis


ii) Tests for Creatinine

a) Jaffe’s Reaction (Test for creatinine)Principle: Creatinine reacts with picric

acid in the alkaline medium to form a reddish colored complex of creatinine picrate

Procedure: Take 5 ml of urine and add an aqueous solution of picric acid. Make the mixture alkaline with NaOH solution. A red color is produced.


ii) Tests for Creatinine

b) Nitroprusside testTo 5 ml of urine add a few drops of sodium

nitroprusside and make the solution alkaline with sodium hydroxide (NaOH).

A ruby red color is formed that turns yellow.This test is also called Wey’s test.


ii) Tests for Creatininec) Nitroprusside -Acetic acid test (Salkowaski

test) Procedure : Take 5 ml of urine, add a few drops

of sodium nitroprusside and then make the solution alkaline with NaOH. A ruby red color is formed that turns yellow.

To the yellow precipitate, add an excess of acetic acid and heat the solution.

A green color is obtained that turns blue upon standing.


ii) Test for CreatinineInterpretation: a) Creatinuria- Creatinuria occurs in uncontrolled

diabetes mellitus, thyrotoxicosis, myasthenia gravis, starvation, infancy, pregnancy, muscular disorders and in growing period.

b) Increased urinary creatinine: Muscular disorders c) Decreased urinary creatinine: Renal failure


iii) Tests for Uric acid

a) Phospho tungstic acid test (For uric acid)

Principle: Uric acid is a reducing agent in alkaline medium. It reduces phospho tungstic acid to tungsten blue.

Procedure: Take 2 ml of urine, add a few drops of phospho tungstic acid reagent followed by a few drops 20% sodium carbonate. Observe the appearance of blue color


iii)Tests for Uric acid

b) Benedict’s testPrinciple- Uric acid is soluble in alkali. The blue

color is developed due to the reduction of phospho tungstic acid by uric acid.

Procedure : To 2 ml of urine , add a few drops of Benedict’s uric acid reagent and add a pinch of anhydrous sodium carbonate and mix. A deep blue color indicates the presence of uric acid.


iii) Tests for Uric acid

Interpretation: a) Increased urinary uric acid: Cancers,

leukemia, administration of ACTH, Wilson's disease.

b) Decreased urinary uric acid: Purine free diet, gout.


Tests for abnormal constituents of urine

Abnormal urineSubstances which are not present in easily

detectable amounts in urine of normal healthy individuals but are present in urine under certain diseased condition are said to be “Abnormal” or “pathological” constituents of urine.


Abnormal constituents of urine

• Reducing sugars• Ketone bodies• Proteins• Blood• Bile salt• Bile pigments and • Urobilinogen


Tests for abnormal constituents of urine

• These constituents are present in normal health but in very small amount and are not detected by less sensitive laboratory methods.

• Under certain pathological conditions their concentration is increased and these are get detected . The urine is said to be ‘Abnormal ’, under such conditions.

04/12/23 Biochemistry for medics- Lecture Notes 50

Tests for reducing sugars

1) Benedict’s TestPrinciple :Benedict's reagent contains sodium

carbonate, copper sulphate and sodium citrate. In the alkaline medium provided by Sodium carbonate, the copper remains as cupric hydroxide. Sodium citrate acts as a stabilizing agent to prevent precipitation of cupric hydroxide. In alkaline medium, sugars form enediols, cupric ions are reduced, and corresponding sugar is oxidized to sugar acid.


Tests for reducing sugarsBenedict’s testProcedure: Take 5 ml of Benedict's reagent,

add 8 drops of urine. Boil for 2 minutes or keep it in the boiling water bath for 5 minutes. A light green, yellow or brick red color is produced depending on concentration of urinary glucose.

Negative test

Positive test


Tests for reducing sugarsObservationsBenedict‘s test is a semi quantitative test. The color of the precipitate gives a rough estimate of the reducing sugars present in the given sample. Green color - Up to 0.5 g%Green precipitate - 0.5-1.0 g%(+)Yellow precipitate -1.0-1.5 g% (++)Orange precipitate- 1.5-2.0 g% (+++) Brick red precipitate- >2.0 g% (++++)04/12/23 53Biochemistry for medics- Lecture Notes

Tests for reducing sugars

2) Fehling Test• Another reduction test• Contains KOH and Sodium potassium Tartrate

in place of Sodium carbonate and sodium citrate in Benedict’s reagent

• Not used any more, since it is less sensitive, less specific and the strong alkali causes caramelisation of the sugars present in the given sample.


Tests for reducing sugarsInterpretation: • Positive Benedict's test signifies Glycosuria. • Glycosuria is a non-specific term. Any reducing

sugar found in urine is denoted by glycosuria• Lactosuria - in lactose intolerance • Galactosuria - in galactosemia • Fructosuria - in hereditary fructose

intolerance • Pentosuria - in essential Pentosuria


GlycosuriaCauses of Glucosuria are: (Glucosuria and Glycosuria are used synonymously)a. Renal glycosuria- pregnancy, hereditary, diseases of renal tubules, heavy metal poisoning .b. Diabetes mellitus c. Alimentary glucosuria d. Hyperthyroidism, hyperpituitarism and hyperadrenalism e. Stress, severe infections, increased intracranial pressure


Glycosuria

Examples of non-carbohydrate substances which give a positive Benedict's reaction are: a) Creatinine b) Ascorbic acid c) Glucuronates d) Drugs: Salicylates, PAS and Isoniazid


Tests for proteins

1) Heat Coagulation testPrinciple: Albumin is coagulated when heated,

which is precipitated at the iso-electric point, when acetic acid is added.

Procedure : Fill 3/4th of the test tube with acidified urine (add few drops of dilute acetic acid) and heat the top half of it. Lower part serves as a control. Note the appearance of turbidity.


Tests for proteinsHeat Coagulation test- Acidification is

necessary because-1) In alkaline medium heating may

precipitate carbonates and phosphates.

2) False negative results may be obtained since the proteins are coagulated by heat at a pH near Isoelectric p H.

3) In alkaline medium proteins may not be precipitated owing to the formation of alkaline meta proteins that are not precipitated upon heating.

The heated upper half shows turbidity due to the precipitation of proteins, the lower half serves as a control for comparison.


Bence Jone’s proteins• Bence Jone’s proteins are light chain

immunoglobulins• Excreted in urine of a patient suffering from

multiple myeloma• These proteins precipitate between 40-60 degree

centigrade• Upon further heating, turbidity disappears to

reappear on cooling• These proteins redissolve on boiling unlike

albumin


Tests for proteins

2) Sulphosalicylic acid testPrinciple: Negatively charged sulpho salicylic

acid neutralizes the positive charge on proteins causing denaturation, and hence precipitation of proteins.

Procedure: To 1 ml of urine add 3 drops of 20% Sulphosalicylic acid. A turbidity or precipitate indicates the presence of proteins.

Absence of cloudiness means absence of proteins.


Test for proteinsS.No. Observation Inference

(Approximate protein concentration) mg/100 ml

1) Barely visible turbidity 52) Distinct turbidity 10-303) Moderate turbidity 40-1004) Heavy Turbidity 200-5005) Heavy

flocculent/precipitation500


Test for proteins

3) Heller’s Nitric acid ring testPrinciple: Concentrated HNO3 causes denaturation

and hence precipitation of proteins. Procedure: Take 3-5 ml of concentrated nitric acid.

Incline the tube and to it add carefully, 2-3 ml of urine, so that it forms the upper layer without disturbing the lower HNO3 layer. In a positive reaction, a white zone of precipitate protein will appear at the junction of two liquids.


Tests for proteins

Interpretation- Insignificant amounts of proteins are excreted in urine in normal health not exceeding 20-80 mg/dl. This small amount is not detectable by routine methods. Under certain conditions, as much as 20 G or more proteins may be excreted per day in urine.The most common type of proteinuria is albuminuria; hence proteinuria and albuminuria are used synonymously.


Proteinuria

When proteins appear in urine in detectable amounts, it is called proteinuria. It can be caused by-a) Increased glomerular permeabilityb) Reduced tubular reabsorptionc) Increased secretion of proteinsd) Increased concentration of low molecular weight proteins in the plasma


Proteinuria

Proteinuria may be- Physiological or PathologicalI) Physiological ProteinuriaCauses include-• Violent exercise• Pregnancy• Postural• Alimentary• Exposure to cold


Proteinuria

II) Pathological proteinuriaI. Pre Renal: • Severe dehydration• Heart diseases• Ascites (due to increased intra-abdominal pressure)• Severe anemia, and• Fever• Collagen diseases• Toxemia of pregnancy


ProteinuriaII. Renal: All inflammatory, degenerative or

destructive diseases of kidney; the most common ones are:

• Nephrotic syndrome, • Pyelonephritis• Acute and Chronic glomerulonephritis • Nephrosclerosis• Tuberculosis of kidney • Renal failure. 04/12/23 68Biochemistry for medics- Lecture Notes

ProteinuriaIII. Post Renal – Also called false proteinuria because in these conditions proteins do not pass through the kidneys.Causes include-•Severe urinary tract infections•Inflammatory, degenerative or traumatic lesions of pelvis, ureters, bladder, prostate or urethra•Bleeding genito urinary tract•Pus in urine•Contamination of urine by semen or vaginal secretions


Tests for Ketone bodies

Rothera’s TestPrinciple: Nitroprusside in

alkaline medium reacts with a ketone group to form a purple ring. It is given by acetone and acetoacetate, but not by Beta hydroxy butyric acid.



Procedure: • Saturate 5 ml of urine with solid ammonium

sulphate and add 0.5 ml of freshly prepared sodium nitroprusside (5%).

• Mix well and add liquor ammonia from the side of tube.

• A purple ring at the junction of the liquid indicates the presence of ketone bodies.



2) Gerhardt’s ferric chloride test Principle: A purplish color is given by aceto

acetate. On boiling acetoacetate is converted to acetone and does not give this test positive. This test is only given by acetoacetate and not by beta hydroxy butyric acid directly.



2) Gerhardt’s ferric chloride test Procedure- Add 10% ferric chloride solution

drop by drop to 5 ml of urine in a test tube. If phosphates are present, precipitates of ferric phosphates may form, that should be filtered off and the ferric chloride is added.

False positive Gerhardt’s test may be obtained with Salicylic acid and Salicylates.



3) Test for β- OH butyric acid• No direct test for β- OH butyric acid• Indirect test is performedProcedure : Add a few drops of Acetic acid to

urine diluted 1:1 with distilled water. Boil for a few minutes to remove acetone and aceto acetic acid. Add about 1.0 ml of H2O2, warm gently, cool, and perform Rothera’s test .



Acetone, acetoacetate and beta hydroxy butyrate are the ketone bodies. Ketonemia and hence ketonuria occurs mostly in conditions of glucose deprivation. Causes of Ketonuria: 1) Uncontrolled diabetes mellitus 2) Starvation 3) High fat feeding 4) Heavy exercise 5) Toxemia of pregnancy


Tests for bile pigments

1) Fouchet’s test Principle: BaCl2 reacts with sulphate in urine to

form barium sulphate. If bilirubin is present in urine, it adheres to precipitate and is detected by oxidation to form biliverdin (Green) with FeCl3 in the presence of trichloro acetic acid. Nitric acid oxidizes bilirubin to biliverdin giving different colors from green to violet.



1) Fouchet’s test Procedure: Take 5 ml of 10% BaCl2 to 10 ml of

urine and filter. Dry the filter paper and add a few drops of Fouchet's reagent (Prepared by adding 10 mg of 10% FeCl3 to 100 ml of 25% TCA). A green color is obtained due to oxidation of bilirubin to biliverdin.



2) Gmelin’s test Principle: Nitric acid oxidizes Bilirubin to Biliverdin giving different colors from green to violet.Procedure: To about 5 ml of concentrated HNO3

in a test tube, add an equal volume of urine carefully so that the two liquids do not mix. At the junction of two liquids various colored rings (Green, blue, red, violet etc.) will be formed. 04/12/23 78Biochemistry for medics- Lecture Notes


3) Iodine testProcedure : Dilute some tincture of iodine with

one to two volumes of water and layer it carefully on to some urine in a test tube, a green ring at the junction of two fluids indicates the presence of Bilirubin.

It is not a sensitive test, can not detect small amount of bilirubin present in the given sample.



Interpretation Bilirubin in urine means increased amount of

conjugated bilirubin because unconjugated bilirubin is water insoluble and is also bound to albumin, hence cannot cross the glomerular membrane.

Causes of bilirubinuria are: 1) Moderate to severe hepatocellular damage 2) Obstruction of bile duct- Intra or extra hepatic In prehepatic jaundice, bilirubin is absent in urine.


Test for Bile salts

Hay’s Sulphur test Principle: Bile salts lower the surface tension allowing

the sulphur powder to sink Procedure: Sprinkle a little dry sulphur powder on the

surface of fresh urine in a test tube taking distilled water as control. Sulphur powder sinks in the presence of bile salts.


Test for Bile salts

Control for comparison

Positive test

In the control, sulphur powder remains immiscible with the underlying liquid. In the positive test, the sulphur powder sinks to the bottom.

Interpretation: Bile salts and bile pigments are present in urine in obstructive jaundice.


Test for Urobilinogen

Ehrlich’s test Principle: The test for urobilinogen is based on the Ehrlich

Aldehyde Reaction. P-dimethylaminobenzaldehyde in an acid medium with a

color enhancer reacts with urobilinogen to form a pink-red color. The optimum temperature for testing is 22° - 26°C. A freshly voided sample is best for optimal results.


Test for UrobilinogenEhrlich’s testProcedure: Take 5 ml of fresh urine in a test tube and add 5 ml

of Ehrlich's reagent to it. Wait for 10 minutes and add 10 ml of saturated sodium acetate solution. A pinkish color indicates the presence of urobilinogen. Porphobilinogen is also detected by Ehrlich's test. The color intensifies upon addition of sodium acetate if Porphobilinogen is there.


Test for Urobilinogen

Interpretation: Urobilinogen is found in urine in hepatic and

prehepatic jaundice. It is present in excessive amount in prehepatic jaundice and is completely absent in post hepatic jaundice. An increased urobilinogen concentration in urine is a sensitive index of liver dysfunction or hemolytic disorders.


Test for blood Benzidine TestPrinciple: Hydrogen peroxide liberated from Hb oxidizes Benzidine to form a colored derivative. Procedure: To 3 ml of saturated Benzidine solution in glacial acetic acid, add 2 ml of urine and add 1 ml of 3% H2O2. A blue or green color develops within 10 minutes indicating the presence of blood. Color developing after 10 minutes is not a positive test but it is due to oxidation of Benzidine by atmospheric oxygen.


Test for blood

Interpretation: Presence of blood in urine is called hematuria. a. Gross hematuria: Urine appears reddish in gross hematuria and

this is observed in renal stones, malignancies, trauma, tuberculosis and acute glomerulonephritis.


Test for blood

b. Microscopic hematuria: Blood is not visible to naked eyes. It is observed in: • Malignant hypertension, •Sickle cell anemia, •Coagulation disorders, •Polycystic kidney disease, •Incompatible blood transfusion, •Auto immune hemolytic anemia.


Urine test strips

• 10 different substances in urine can be detected.

• Easy, quick and bed side procedure


Further reading

1) http://www.lulu.com/shop/namrata-chhabra-and-kavish-ramessur/clinical-approach-to-practical-biochemistry/ebook/product-21016914.html

2) http://www.namrata.co/category/practical-biochemistry/normal-urine-analysis/

3) http://www.namrata.co/category/practical-biochemistry/abnormal-urine/04/12/23 Biochemistry for medics- Lecture Notes 90

http://www.lulu.com/shop/namrata-chhabra-and-kavish-ramessur/clinical-approach-to-practical-biochemistry/ebook/product-21016914.html




http://www.namrata.co/category/practical-biochemistry/normal-urine-analysis/

http://www.namrata.co/category/practical-biochemistry/normal-urine-analysis/

http://www.namrata.co/category/practical-biochemistry/abnormal-urine/

http://www.namrata.co/category/practical-biochemistry/abnormal-urine/

urinalysis- methods, observations and clinical significance

Education

volume of excreted urine

medics lecture notes

introduction urine

normal color of urine

increased volume of

minimum volume of urine

specific gravity of

physical examination