URINALYSIS (MLT 305) LECTURE TWO

1. URINALYSIS (MLT 305)LECTURE TWO Dr. Essam H. Jiffri

2. BLOOD • - Blood may be present in the urine either in the form of intact red blood cells (hematuria) or as the red blood cell destruction product hemoglobin (hemoglobinuria). • - Blood present in large quantities can be detected visually; hematuria produces a cloudy red urine and hemoglobinuria appears as a clear red specimen.

3. BLOOD • Any amount of blood greater than 5 cells per microliter of urine is considered clinically significant, it is not possible to rely on visual examination to detect the presence of blood. • - The microscopic examination can be used to differentiate between hematuria and hemoglobinuria.

4. BLOOD • REAGENT STRIP REACTIONS • - Chemical tests for blood utilize the pseudoperoxidase activity of hemoglobin to catalyze a reaction between: • - hydrogen peroxide and the chromogen tetramethylbenzidine • to produce an oxidized chromogen, which has a green-blue color. • hemoglobin • H2O2 + Chromogen Oxidized Chromogen + H2O • peroxidase

5. BLOOD • REAGENT STRIP REACTIONS • - Two color charts are provided that correspond to the reactions that occur with hemoglobinuria and hematuria. • - In the presence of free hemoglobin: • - A strongly positive blue will appear on the pad. • - In contrast, intact red blood cells: • - A speckled pattern will appear on the pad.

6. BLOOD • CLINICAL SIGNIFICANCE OF URINE BLOOD • Hematuria • 1. Renal calculi • 2. Glomerulonephritis • 3. Pyelonephritis • 4. Tumors • 5. Trauma • 6. Exposure to toxic chemicals or drugs • 7. Strenuous exercise

7. BLOOD • CLINICAL SIGNIFICANCE OF URINE BLOOD • Hemoglobinuria • 1.Transfusion reactions • 2.Hemolytic anemia • 3. Severe burns • 4. Infections • 5. Strenuous exercise

8. BLOOD • CLINICAL SIGNIFICANCE OF URINE BLOOD • Myoglobinuria • 1. Muscular trauma • 2. Prolonged coma • 3. Convulsions • 4. Muscle-wasting diseases • 5. Extensive exertion

9. BILIRUBIN • - The appearance of bilirubin in the urine is the first indication of liver disease and is often detected long before the development of jaundice. • - Bilirubin provides early detection of hepatitis, cirrhosis, gallbladder disease, and cancer, and should be included in every routine urinalysis.

10. BilirubinBilirubin, a highly pigmented yellow compound, is a degradation product of haemoglobin

11. Bilirubin • OXIDATION TESTS (FOUCHET’S TEST) • - Urine containing bilirubin usually appears dark yellow or amber and produces a yellow foam when shaken, this foam test was actually the first test for bilirubin. • - Oxidation tests utilize the ability of feric chloride dissolved in trichloracetic acid (Fouchet's reagent) to oxidize bilirubin to biliverdin, producing a green color.

12. Bilirubin • REAGENT STRIP (DIAZO) REACTIONS • Routine testing for urinary bilirubin by reagent strip utilizes the diazo reaction, in an acid medium to produce colors ranging from increasing degrees of tan or pink to violet, respectively. • Questionable results should be retested using the Ictotest which produces a more sharply colored diazo reaction. • - Colors other than blue or purple appearing on the mat are considered negative.

13. Bilirubin • CLINICAL SIGNIFICANCE OF URINE BILIRUBIN • 1. Hepatitis • 2. Cirrhosis • Biliary obstruction

14. - The presence or absence of bilirubin can be used in determining the cause of clinical jaundice. ( Urine Bilirubin and Urobilinogen in Jaundice ) Bilirubin

15. UROBILINOGEN • Like bilirubin, urobilinogen is a bile pigment that results from the degradation of hemoglobin. • It is produced in the intestine by the oxidation of bilirubin by the intestinal bacteria. • - Approximately half of the urobilinogen is reabsorbed from the intestine into the blood, recirculates to the liver, and is secreted back into the intestine through the bile duct.

16. UROBILINOGEN • The urobilinogen remaining in the intestine is excreted in the feces, where it is oxidized to urobilin, the pigment responsible for the characteristic brown color of the feces. • Urobilinogen appears in the urine because, as it circulates in the blood en route to the liver, it passes through the kidney and is filtered by the glomerulus. • - A small amount of urobilinogen less than 1 mg/dl or 1 Ehrlich unit is normally found in the urine.

18. UROBILINOGEN • EHRLICH'S TUBE TEST • The reagent used in all tests was • p-dimethylaminobenzaldehyde (Ehrlich's reagent), addition of Ehrlich's reagent to urine containing urobilinogen produces a cherry red color. • - Positive results in dilutions greater than 1 to 20 were considered significant.

19. UROBILINOGEN • EHRLICH'S TUBE TEST • An Ehrlich unit is essentially equal to 1 mg of urobilinogen. • - Normal values for females are 0.1 to 1.1 Ehrlich units; and for males, 0.3 to 2.1 Ehrlich units, these values are based on the recommended 2-hour specimen collected after the noon meal between 2 and 4 PM,which is the time of greatest urobilinogen excretion.

20. UROBILINOGEN • CLINICAL SIGNIFICANCE OF URINE UROBILINOGEN • 1. Early detection of liver disease • 2. Hemolytic disorders

21. NITRITE • - The reagent strip test for nitrite provides a rapid screening test for the presence of urinary tract infection.

22. NITRITE • REAGENT STRIP REACTIONS • Nitrite is detected by the Greiss reaction: • - nitrite at an acidic pH reacts with an aromatic amine to form a diazonium compound that react with quinolin compound to produce a pink color.

23. NITRITE • CLINICAL SIGNIFICANCE OF URNE NITRITE • 1. Cystitis (initial bladder infection) • 2. Pyelonephritis (an inflammatory process of the kidney and adjacent renal pelvis) • 3.Evaluation of antibiotic therapy • 4. Monitoring of patients at high risk for urinary tract infection • 5. Screening of urine culture specimens (detection of bacteruria)

24. SPICIFIC GRAVIIY • The addition of a specific gravity testing area to Multistix has eliminated: • time-consuming step in routine urinalysis • provided a convenient method for routine screening. • - It is not recommended to replace osmometry or refractometry for critical fluid monitoring.

25. SPICIFIC GRAVIIY • REAGENT STRIP REACTION • - The test is based on the change in pK- (dissociation constant) of poly methyl vinyl- ethermaleic anhydride.

26. SPICIFIC GRAVIIY • CLINICAL SIGNIFICANCE OF URINE SPECIFIC CRAVITY • 1. Patient hydration and dehydration • 2. Loss of renal tubular concentrating ability • 3. Diabetes insipidus • 4. Determination of unsatisfactory specimens due to low concentration

27. LUKOCYTES • - One of the most frequent findings in the routine urinalysis is the presence of leukocytes, indicating a possible infection of the urinary tract. • - Detection of leukocytes was previously made only by microscopic examination of the urinary sediment.

28. LUKOCYTES • REAGENT STRIP REACTION • The chemical reaction is enzymatic, utilizing esterases present in granulocytic white blood cells to hydrolyze indoxylcarbonic acid ester to produce indoxyl, which reacts with a diazonium salt to create a purple color. • leukocyte • indoxylcarbonic acid ester indoxyl + diazonium salt (purple color) • esterases • - It is recommended that trace reactions be repeated on a fresh specimen and that microscopic examinations be performed on all positive specimens.

29. LUKOCYTES • CLINICAL SIGNIFICANCE OF URINE LEUKOCYTES • 1. Urinary tract infection • 2. Screening of urine culture specimens