Urine examination

It gives basic things regarding urinalysis and will be very useful for medical students, house surgeons, laboratory technicians and postgraduates in medicine.

1. Urine examination Dr.S.Sethupathy,M.D.,Ph.D ., Professor of Biochemistry, Rajah Muthiah Medical College, Annnamalai University

2. Kidney functions Excretion waste products such as urea, Creatinine, uric acid Maintenance of acid base balance Maintenance of water and electrolyte balance Hormone function – Erythropoietin Regulation of blood calcium level – Formation of calcitriol by 1 α – hydroxylase

3. Urine examination A complete physical, chemical and microscopic examination plays a an important role in diagnosis of renal and urinary tract diseases .

4. COLOR Normal urine - light yellow to amber Due to the presence of a yellow pigment, urochrome The more concentrated urine - the deeper the color. Deviations from normal color - certain drugs (B comp), vegetables such as carrots, beets, and rhubarb. Hematuria and hemoglobinuria - Red Milky white- Infection, Chyluria Yellowish green / orange – Bilirubin , bacterial infection

5. Abnormal colors and causes

6. ODOR Slightly aromatic, characteristic of freshly voided urine. Urine becomes more ammonia-like upon standing due to bacterial activity.

7. Odor Condition Aromatic odor Normal Fruity smell ( acetone) Diabeteic ketosis (Type 1) Fishy odor UTI Ammoniacal odor UTI caused by pseudomonas & proteus Mousy odor Phenyl ketonuria Burnt sugar Maple syrup urine disease

8. TURBIDITY Normal urine is transparent or clear Cloudy urine – causes RBCs, WBCs Epithelial cells Bacteria – Pyuria Casts Crystals Lymph – chyluria Semen

9. casts Urinary casts   - microscopic cylindrical structures produced by the kidney and present in the urine in disease states. Casts first described by Henry Bence Jones Formed in the  distal convoluted tubule and collecting ducts of  nephrons In urine, detected by microscopy, formed by   Tamm– Horsfall mucoprotein secreted by renal tubule cells, and also by albumin in   proteinuria . Generally 15-20 squamous epithelial cells/ hpf or more indicates   urinary  contamination. Hyaline  casts   may be seen in healthy subjects. Other types of  casts  are suggestive of  renal  disease.

10. Urinary casts

11. RBC casts

12. Leucocyte (WBC) casts

13. Hyaline casts

14. Granular casts

15. Pigment casts

16. crystals

17. Chyle in urine Milky or hazy appearance of urine - high phosphate or huge pus cells. Phosphates excluded by adding few drops of 5% acetic acid. Pyuria -by centrifuging the sample that gives a clear upper and a hazy lower zone of the fluid and then by microscopy. In chluria , fat solvent (ether) almost completely clear the opacity. Chylomicrons -visualized under microscope with dark ground illumination or stained with Sudan III.  Triglycerides estimation- controls no TGL.

18. Semen in urine In retrograde ejaculation semen  goes backward into the bladder. It is not a harmful condition. The  semen  mixes with  urine  and passes out of the body the next time the man urinates.

19. ph Ranges from 4.5 - 8.0. Average is 6.0, slightly acidic. Under 5.0 is acidic,  higher than 8.0 is alkaline Vegetarian diets increase alkalinity. Bacterial infections also increase alkalinity.

20. Acidic urine High protein diets increase acidity. Dehydration Diabetic ketoacidosis Diarrhea starvation

21. Alkaline urine gastric suctioning , pyloric obstruction, vomiting - that takes away stomach acids kidney failure kidney tubular acidosis respiratory alkalosis urinary tract infection

22. SPECIFIC GRAVITY Specific gravity measures the ability of the kidneys to concentrate or dilute urine depending on fluid intake. Normal range 1.005 - 1.030 , average range 1.010 - 1.025. Low specific gravity is associated with conditions like diabetes insipidus , excessive water intake, diuretic use or chronic renal failure. High specific gravity levels are associated with diabetes mellitus, adrenal abnormalities or excessive water loss due to vomiting, diarrhea or kidney inflammation. A specific gravity that never varies is indicative of severe renal failure.

23. Volume

24. HIGH S.G Volume loss (dehydration, vomiting, diarrhea, fever) Heart failure Renal artery stenosis Shock Syndrome of inappropriate antidiuretic hormone Diabetes mellitus- glucosuria

25. Low s.g Diabetes insipidus Excessive water intake Diuretic use Chronic renal failure (fixed S.G- 1.010). Renal failure , Pyelonephritis , Glomerulonephritis Psychogenic polydipsia Malignant hypertension

26. Abnormal constituents Glucose –   Glycosuria Normally the filtered glucose is reabsorbed by the renal tubules Renal threshold for glucose- Blood glucose level 160-180 mg/dl If blood glucose levels exceeds renal threshold level, glucose spills over into the urine. Main cause: diabetes mellitus  Renal glucosuria - reduced renal threshold level Blood glucose level-normal but urine glucose positive

27. Protein (albumin)   Albumin do not pass through glomerulus . Presence indicates abnormal increased permeability of the glomerulus membrane. Non-pathological causes are: pregnancy, physical exertion, increased protein consumption. Pathological causes are: glomerulonephritis , bacterial toxins, chemical poisons. 

28. Urinary protein - Albuminuria Less than 30 mg /24 hrs or 30 mg/gm Creatinine or 30 µg/mg creatinie is  normal . 30 – 300 mg /24 hrs or 30 -300 mg/gm creatinine or 30-300 µg/mg Creatinine is  microalbuminuria More than 300 mg / day – frank albuminuria Healthy albumin to Creatinine ratio: less than or equal to 3.5 mg/ mmol ( 30mg / gm Creatinine) - Creatinine mol.wt : 113

29. Urinary ketones Ketone bodies - acetoacetic acid, beta- hydroxybutyric acid, Causes: diabetes mellitus, starvation, ketogenic diet drinking excess alcohol excessive vomiting , pregnancy illness or infection heart attack , emotional or physical trauma medications, such as corticosteroids and diuretics

30. Urinary ketones range Under 0.6 millimoles per liter or 6mg/dl -Normal ketone level 0.6 to 1.5 millimoles per liter or 6-15 mg/dl higher than normal; test again in 2 to 4 hours 1.6 to 3.0 millimoles per liter or 16- 30 mg/dl –Moderate Above 3.0 millimoles per liter or > 30mg/dl - high

31. bilirubin Fouchet’s test:  This is a simple and sensitive test. Five ml of fresh urine in a test tube is mxed with 2.5 ml of 10% of barium chloride .A precipitate - barium sulphate-bilirubin complex forms Filter and spread the precipitate on a filter paper. one drop of Fouchet’s reagent is added to the precipitate. ( Fouchet’s reagent consists of 25 grams of trichloroacetic acid, 10 ml of 10% ferric chloride, and distilled water 100 ml). Immediate development of blue-green color around the drop indicates presence of bilirubin . Causes: liver disorders, cirrhosis, hepatitis, obstruction of bile duct 

32. Fouchet’s test - positive Reagent strips or tablets impregnated with diazo reagent:  :Based on reaction of bilirubin with diazo reagent; Color change is proportional to the concentration of bilirubin . Tablets ( Ictotest ) detect 0.05-0.1 mg of bilirubin /dl of urine; Reagent strip tests are less sensitive (0.5 mg/dl).

33. Urobilinogen Normal – 0.2 mg/dl - 1mg/dl Less than 0.2 mg/dl - low More than 1 mg /dl – high High urobilinogen level Hemolytic anemias , malaria False Positive Results - Elevated nitrate in the urine High carbohydrate intake Timing (test is done later in the afternoon) Drugs that make the urine red, such as phenazopyridine ( Pyridium )

34. Low urobilinogen -- cholestasis - causes include  : Bile duct blockage (gallstones, cysts, and tumors) Liver disease/damage Pregnancy Severe infection Pancreatic cancer Broad-spectrum antibiotics False Negative Results Exposure of urine sample to direct sunlight– urobilinogen breaks down Substances that acidify urine (e.g. vitamin C)

35. Hematuria - causes Kidney infections   ( pyelonephritis ).   A bladder or kidney stone.   Enlarged prostate.   Kidney disease.  . Cancer.   Inherited disorders.  Sickle cell anemia Alport syndrome, which affects the filtering membranes in the glomeruli of the kidneys. Kidney injury.  A blow or other injury to your kidneys from an accident or contact sports can cause Medications.   drug cyclophosphamide and penicillin , aspirin, heparin can cause urinary bleeding. Strenuous exercise.  It's rare for strenuous exercise to lead to gross hematuria ,

36. Hemoglobinuria -causes Acute  glomerulonephritis Burns , Renal cancer , Malaria Microangiopathies , Transfusion reactions IgM  autoimmune hemolytic anemia Glucose-6-phosphate dehydrogenase deficiency Pyelonephritis Sickle cell anemia Tuberculosis of the urinary tract March hemoglobinuria  secondary to repetitive impacts on the body, usually the feet Athletic nephritis secondary to strenuous exercise Acute lead poisoning

37. dip-stick test – hematuria A nondiagnostic screening test. A positive result is due to oxidation of a test-strip reagent; it does not confirm that blood cells are present. Factors that can cause a positive result on a dipstick test include hemoglobinuria , myoglobinuria , concentrated urine, menstrual blood in the urine sample, and rigorous exercise False-positive results can occur (certain dyes or drugs, beets, oxalates). The strip is read in a min. (sensitivity of 100% and a specificity of 99% in detecting 1-5 RBCs per high-power field ( hpf ).

38. dip-stick test for hematuria Confirm presence of RBCs microscopically. If the specific gravity of the urine is very low (< 1.007), microscopy can fail to detect owing to cell lysis . Repeat the test after restricting the patient’s fluid intake Other investigations should be avoided, and the dipstick and microscopic urinalysis should be repeated twice within 2 weeks.

39. leukocytes and nitrites Normal - 0-5  WBCs  per high power field ( wbc / hpf ) High number of leukocytes may   indicate  the presence of   urinary tract infection If the test for leukocyte esterase is positive but finds no nitrite, an infection may still be present. E. coli  bacteria are most commonly associated with nitrites in the urine.

40. Test Report format Results Physical- color and odor Turbidity Specific gravity pH Chemical - protein Glucose ketones urobilinogen bilirubin blood leukocytes nitrites Microscopic - RBCs Leukocytes Crystals Casts Bacteria /yeast

41. Thank you