This document provides an overview of urinalysis, which is a key test in clinical nephrology. It describes the aims of urinalysis to examine the physical characteristics, chemical composition, cellular elements, and microorganisms in urine. It then explains how dipstick tests can assess various analytes like pH, protein, blood, and others. The document also covers urine microscopy to examine elements like erythrocytes, leukocytes, epithelial cells, casts, crystals, and microorganisms that can indicate underlying kidney conditions.

1. URINALYSIS – The ‘cornerstone’ of Clinical Nephrology N.Gopalakrishnan, MD, MRCP, DM

2. ‘ Sick Lady and Doctor’ 16 th century painting by Caspar Netscher (AJKD,2007)

3. Urinalysis - Aims Physical characteristics Chemical composition Cellular elements Microorganisms

4. Abnormal Colour of urine White Chyle,pus Yellow Bilirubin Pink / reddish brown RBCs, haemoglobin,myoglobin Brown / black Methaemoglobin, homogentisic acid Green Pseudomonas

5. Dipstick pH Protein Blood Specific gravity Glucose Leucocytes Nitrite Bilirubin Urobilinogen Ketones

6. pH pH Dipstick – pH 4.5 to 8.5; less accurate when pH is < 5 or >8 For accurate estimation, pH meter with glass electrode is mandatory

7. Specific gravity Denotes weight of solutes Inaccurate surrogate of osmolality Methods: Hydrometer Refractometer Dipstick Range: 1.001 – 1.035 Assesses concentrating ability Differentiation between pre renal azotemia & ATN

8. Protein Heat coagulation Sulphosalicylic acid Dipstick

9. Dipstick - protein Protein indicator strips – tetrabromophenol blue or bromocresol blue Colour change according to protein concentration Trace to 4+ trace 5 – 20 mg/dl 1+ - 30, 2+ - 100, 3+ - 300, 4+ - > 2000 mg/dl

10. Dipstick - protein Highly alkaline urine - false positive reaction Quantification – influenced by urinary concentration Less sensitive to globulin,haemoglobin & light chain Urine negative by dipstick but positive with sulphosalicylic acid – highly suspicious for light chains

11. Henry Bence Jones Light chains Myeloma Precipitate 40- 60 C Dissolves 100 C Reappears on cooling

12. Preparation of sample for microscopy Second urine of the morning after discarding initial few millilitres Analysis within 2 – 4 hrs Centrifuge (10 ml) at 2000 rpm for 10 min Remove 9.5 ml of supernatant Resuspend sediment with pipette in the in remaining 0.5 ml Transfer 50 ul with pipette on to a slide

13. Microscopy Phase contrast microscope – ideal High sensitivity for hyaline casts & RBCs with low Hb content For RBC morphology Filters to polarize light – for lipids & unusual crystals

14. Erythrocytes > 2 -3 / HPF --- Haematuria Isomorphic haematuria – from collecting system Dysmorphic haematuria – from renal parenchyma

15. Dysmorphic RBCS Glomerular origin Acanthocytes – sensitive indicator

16. Leucocytes Indicate urinary tract inflammation ‘ Glitter cells’ – swollen polymorphs with prominent granules UTI, interstitial nephritis, glomerulonephritis

17. Sterile pyuria Tuberculosis Partially treated UTI Steroids Calculi Prostatitis Bladder tumour Papillary necrosis

18. Eosinophiluria Acute allergic interstitial nephritis Atheroembolism Rapidly progressive glomerulonephritis Schistosomiasis Hansel’s stain

19. Renal tubular epithelial cells (RTECs) Larger than WBCs Few cells are normal Indicate tubular damage or inflammation ATN, interstitial nephritis

20. Casts in the urine Tubular moulds Tamm Horsfall protein forms the matrix Hyaline casts – base for other casts

21. RBC cast Hyaline cast + RBC Always pathological

22. RBC cast Hallmark of Nephritic sediment

23. WBC cast Pyelonephritis Glomerulonephritis

24. ‘ Dirty brown’ cast Acute Tubular Necrosis

25. Fine granular cast Derived from altered serum proteins Usually, pathological

26. Coarse granular cast Result from degeneration of embedded cells Usually pathological

27. Broad casts (Waxy cast) Form in dilated, atrophic tubules More refractile than hyaline casts Usual in chronic renal insufficiency

28. Telescoped urine sediment Plethora of findings RBCs, RBC casts, WBCs, granular casts, broad casts,etc Classically seen in SLE

29. Crystals in urine Common crystals Pathological crystals Crystals due to drugs

30. Pathological crystals Cystine - Cystinuria Cholesterol – massive proteinuria 2,8 dihydroxyadenine – Adeninie phosphoribosyl transferase deficiency

31. Drugs causing crystalluria Drug overdose Dehydration Hypoalbuminemia Urine pH Acyclovir Indinavir Sulphadiazine Amoxycillin Vitamin C (oxalate)

32. Cystine crystals Always pathological Pathognomonic of cystinuria

33. Uric acid crystals Rhomboid Hyperuricosuric conditions Acute uric acid nephropathy

34. Calcium Oxalate Monohydrate:’dumb bell’ Byhydrate: ‘envelope’

35. Triple phosphate crystals ‘ Coffin lid’shaped Rectangular with beveled ends

36. Blood Depends on peroxidase activity of haemoglobin Blood, haemoglobin & myoglobin test positive Dipstick positive for blood, but no RBCs in microscopy – haemoglobin or myoglobin

37. Microorganisms Bacteria Yeasts Trichomonas

38. Nitrite screening test For detection of bacteriuria Bacteria convert urinary nitrate to nitrite which activates a chromogen False negative – Enterococcus

39. Oval fat bodies Macrophages filled with fat droplets Proteinuric conditions

40. Microalbumin dipsticks For screening for microalbuminuria Colorimetric detection of albumin bound to gold – conjugated antibody

41. Let us uphold the ancient tradition! THANK YOU