1. Interpretation of abnormalities in urine
Shiva Seyrafian
Isfahan University of Medical Sciences
20/8/ /10/2012

2. The aim of this lecture Urine tests (GFR and Proteinuria)
Urinalysis and urine sediment

3. What you should learn at the end of this lecture
To know what are the urine tests.
How do we measure urine tests?
What is urinalysis?
How do we exam urinalysis?
What is the benefit of learning urine tests and urinalysis?

4. Tests of Glomerular Filtration Rate
Creatinine Clearance
Normal finding : male : ml/ min female : ml /min

5. Calculation of creatinine clearance
24 hour urine collection
C cr = U cr x V/ P cr
2- Cockroft- Gault Formula
C cr = (140 – age in years) x ( lean body weight in Kg) / S cr x 72
For women multiply final value by 0.85 OR put 85 instead of 72.
3- Modification of Diet in Renal Disease Formula
GFR = 186 X (Cr) x age x [0.742 (if woman)]
Normal range = ml/min/ 1.73 m2

6. Low Cr clearance:
Acute renal failure (ATN, AIN, Acute GN)
Chronic renal failure: Chronic glomerulonephritis, chronic HTN, DM
UTO
Old age

7. Tests that predict kidney disease
Albumin/ Creatinine Ratio (ACR or Microalbumin)

8. Albumin Creatinine Ratio (Microalbumin)
In health, there is very little or no albumin in the urine
Most dip sticks report albumin at greater than 150 mg/L
Normal microalbumin: mg/24hrs

9. Urinary Albumin – cont’d
Detection of low levels of albumin (even if below dipstick cut-off) is predictive of future kidney disease with diabetes
Very significant variation usually requires repeat collections
Microalbuminuria: DM, Hypertension and early GN

10. Urinalysis The most commonly performed
As a screening procedure for asymptomatic individual.
To confirm the presence of renal disease, diabetes, or, more rarely, liver disease.
can be performed in emergency rooms, outpatient clinics, private physicians' offices, and patients' homes.
Routine examination of urine continues to be one of the most commonly performed clinical laboratory procedures, usually as a screening procedure for asymptomatic individual, to confirm the clinical impression of the presence of renal disease, diabetes, or, more rarely, liver disease.
can be performed in a variety of clinical settings, including emergency rooms, outpatient clinics, private physicians' offices, and patients' homes.

11. Urinalysis
Three types of urinalysis can be performed: 1-dipstick urinalysis, 2- microscopic urinalysis, 3-cytodiagnostic urinalysis (specialized analyses) ,2= routine urinalysis
Cytodiagnostic urinalysis is more time- consuming than traditional microscopic analysis

12. Specimen Collection Midstream, catheterized, suprapubic aspiration
Ideally within 30 minutes of collection
Specimens > 2 hours old are inaccurate
Can be refrigerated at 4oc up to 6 hours
Amorphous urate may precipitate
Should return to room temperature

14. Urinalysis
macroscopic analyses consisting of physicochemical determinations (appearance, specific gravity), and multi-parameter reagent-strip measurements of biochemical constituents,
microscopic examination of urinary sediment: hematuria, pyuria, cylindruria (casts), crystalluria, and others.

16. Physical Examination of Urine physicochemical determinations
Volume ( ml/ day)
Odor (Mild, inoffensive odor)
Appearance (color and turbidity)
Many laboratories may also be equipped with refractometer that can relate density of a solution to specific gravity. Refractometers work on the principle that light passing from a transparent medium of one density to a medium of another density, will change its velocity and therefore the direction in which the beam of light is moving. This change in direction, or the bending, of light is called refraction. The refractivity of a solution is dependent, in great part, on the total mass of solids dissolved in that solution. The refractive index scale can be calibrated to measure the specific gravity of most urine sample, that is up to g/mL
Osmolality is usually measured by an osmometer, most frequently by a freezing point osmometer. Osmolality is a measure of the number of particles per unit mass, whereas the specific gravity is a reflection of the density (mass per unit volume) of the suspended particles.

17. Bad odor to the urine Either cystitis or vaginitis
Look for: -Lost and forgotten tampon -Yeast -Trichomonas -Bacterial vaginosis -Asparagus eating -Ampicillin intake

19. Color of urine

21. urine color due to Metronidazol

22. Physical Examination of Urine physicochemical determinations
iv. Specific gravity: refractometer [measures the density (mass per unit volume) of the suspended particles]
The normal range is to g/mL. A value of or greater indicates good renal function

25. Physical Examination of Urine physicochemical determinations
V. Osmolality: osmometer ( the number of particles per unit mass).
The healthy kidney is capable of producing urine with a wide range of concentrations, from 50 to mOsm/kg. Normally, a urine's osmolality will range from approximately one-sixth to four times the osmolality of normal serum (280 to 290 mOsm/kg).

26. Physical Examination of Urine Reagent-strip testing urine pH
The urinary pH range is usually 4.7 to Extremely acidic or alkaline urine usually indicates a poorly collected specimen.
More acidic with increased meat intake
More alkaline with vegetarian diet
High pH with prolonged storage or urea splitting organisms, diuretic therapy, vomiting, ,gastric suction and alkali therapy.

28. Normally not detectable in the urine
Chemical Examination of Urine Reagent-strip testing Blood and myoglobin
Normally not detectable in the urine
Oxidizing agents such as povidone - iodine and myoglobin will cause a positive reaction
Positive dipstick without RBCs suggests hemolysis or rhabdomyolysis.

29. Chemical Examination of Urine Reagent-strip testing
Bilirubin: no detectable in the urine
Urobilinogen: 2-10 mg/L
Only conjugated bilirubin is passed into the urine.
In hemolysis urine urobilinogen is often positive
False positive test for urine bilirubin can occur if the urine is contaminated with stool
Prolonged storage and exposure to light can lead to false negative results.

30. Chemical Examination of Urine Reagent-strip testing
Sugars: not detectable sugars in the urine.
Ketones: not detectable in the urine
Nitroprusside reaction used to detect ketones (acetone and acetoacetate)
b-OH butyrate is not normally detected

31. Chemical Examination of Urine Reagent-strip testing
Nitrites: detect bacteriuria: measures the nitrite formed from converaion of nitrates to nitrites by certain bacteria in urine.
Normally does not contain detectable nitrite.
False negative:
Ascorbic acid and high urine SG
Low urinary nitrates (due to diet)
Rapid transit of urine (takes 4 hrs to convert nitrates to nitrites in bladder )
Degradation of nitrites (prolonged storage of urine)
Gram positives, N. gonorrhea, M. TB.

32. Chemical Examination of Urine Reagent-strip testing
Leukocytes: pyuria (leukocytes in urine) are based on the presence of intracellular esterases released from lysed granulocytes, .
Normally does not contain detectable leukocytes.
False positive
Long standing urine, more granulocyte lysis
Vaginal contamination

33. Normal Proteinuria 30 to 150 mg/day
Usually only small proteins (<20,000 daltons) pass across capillary wall and most are reabsorbed in prox. tubules e.g., a2-microglobulin, apoproteins, enzymes, peptide hormones
Tamm-Horsfall protein (uromodulin)
High m. wt. 23 x 106 daltons glycoprotein
Thick ascending limb and distal convoluted tubule
IgA and urokinase in small amounts

34. False Negative Results Bence Jones proteins
Heavy-chain proteins
False Positive Result Alkaline urine
Sulfosalicylic acid:
False negative Alkaline urine

36. Microscopic Examination Of Urine

37. Microscopic Examination
Cells
Casts
Crystals
Organisms
Artifacts

38. Chemical Examination of Urine – Microscopic examination of urine
Red blood cell: Less than 3 erythrocytes per high- powered field
White blood cell: Less than 5 leukocyte, per three high-power fields (400X) cells/mL
Twice RBC size, cytoplasmic granulation
Inflammation or infection
Eosinophils, best seen with Hansel’s stain or Wright’s stain

39. RBC

42. WBC

43. Epithelial Cells Squamous, transitional, renal epithelial cells
Squamous epithelial cells
Large flat, 30 to 50 micrometers in diameter
Nucleus to cytoplasm size ratio is 1:6
Contamination from distal genital tract

45. Squamous epithelial cell

46. Renal epithelial cell

47. Casts
Renal casts are cylindrical structures that are formed in the nephron and excreted in the urine. Casts are significant because of their localizing value. Casts are composed of mucoprotein, or uromucoid, (Tamm- Horsfall protein), which is always present in urine, usually in solution.

48. Casts
The Tamm- Horsfall mucoprotein is produced by the tubular epithelial cells lining the ascending limb of the loop of Henle.
Casts are formed when urine stasis exists, which allows uromucoid to precipitate.
Increased concentrations of protein and salts and a low urine pH all contribute to cast formation.

49. Casts
Casts: Less than 3 hyaline casts, zero to one granular cast, and no pathological cast per low-power field (100X).
Casts include:
RBC
WBC
Epithelial
Granular
Hyaline
Fatty
Waxy

50. RBC Cast

51. RBC Cast

52. WBC Cast

53. WBC Cast

54. Hyaline cast

55. Granular cast

56. Waxy cast

57. Fat droplets, Oval fat bodies in nephrotic syndrome

58. Nephrotic syndrome

59. Renal epithelial cell cast in ATN

60. Crystals Least clinically important
Crystals exist with/without presence of stones
Cooling urine will have some crystal precipitate
More in concentrated urine
Crystals: Small numbers of common, nonpathological crystals, such as uric acid or phosphate crystals.

61. No specific disease,
Present in Ca Ox stones and ethylene glycols toxicities

62. No specific disease,
Present in Ca Ox stones and ethylene glycol toxicities

63. No specific disease
Present in uric acid stones

64. No specific disease
Present in uric acid stones

65. Specific in cystinuria

66. Coffin lid

68. Fungus, parasites, or viral inclusion cells: None.
Bacteria: Less than 10 bacteria per high- power field (400X).

71. Summary Urinalysis is used as a routine test.
GFR, proteinuria and urinalysis are the most important tests.
cellular casts are more important than crystals.