Urine dipstick• Screening for disease• Fresh urine is collected into clean dry container• Reagent strip immersed in the urine specimen, ensure all the reagent blocks are covered.• Errors in results
• Three urine samples are shown. The one at the left shows a red, cloudy appearance. The one in the center is red but clear. The one on the right is yellow, but cloudy.
Parameters in urine dipstick test• Glucose• Bilirubin• Urobilinogen• Ketones• Specific gravity• pH• Protein• Blood• Nitrite• Leucocytes
Physical examination of urine• Volume a) physiological factor -increase intake of water -temperature -physical activity-others due to diuretic drugs, coffee and alcohol-normal adult urine volume : 600-1200ml/hour-difference in urine volume due to: polyuria, oliguria, anuria and nocturia
• Colour - normal : pale yellowish- urochrom pigment - abnormal : due to food intake and drugsRed : beets, rhubarb (alkaline urine)Orange-yellowish : carrot, antibioticGreen, blue-green : drugs eg: amitryplineDark brown : drugs eg: methyldopa, metronidazole- abnormal : due to pathologicalRed/maroon : rbc, hemoglobin, myoglobin‘wine-red’ : porphyrinDark brown : melanin, homogentisic acidYellowish-brown orgreenish-brown : bilirubin, bile pigment
Normal urine composition• Urea- End product of protein metabolism- 50% from urine composition- 25-30 g/24hr• Uric acid- End product of purine metabolism- 0.5-1 g/24hr• Creatinine- Skeletal muscle tissue
• Creatine- Can be found in muscle tissues in form of phosphocreatin• Sulphur- Protein intake• Indican- Triptophan katabolism in intestine• Ammonia- Final product of protein metabolism
• Chloride- Second largest composition found in urine- Excreted in form of NaCl : 10-15g/24hr urine• Phosphate- Protein intake- 1.1g/24hr urine
Pathological urine composition• Glucose• Protein• Ketones• Pus cells• Red blood cells• Lipid• Amino acid• Bile pigment• Calculi
Microscopic sediment of urine• Cells -rbc, wbc, squamous epithelial cells, urethral epithelial cells• Casts- Represent a collection of protein and cellular debris in a kidney tubule- Eg: hyaline : occasionally found in normal urine but their number is increased in renal diseases.- Cellular cast: one or more type of cells are trapped during their formation. Eg; pus cell casts, red cell casts, epithelial casts, and mixed cellular casts.- Granular casts : fine granules appear in glomerular and tubular renal disease.
Type of Urine Sample & CollectionSample Sampling PurposeMorning sample First urine in the Pregnancy test, morning microscopic testRandom sample No specific time Routine screening, chemical & FEMEPostprandial 2 hours after meal Determine glucose in diabetic monitoringMidstream/clean Discard first few ml, Culturematch collect the rest2 hours Within 2 hours period Determine urobilinogen24 hours Within 24 hours period Determine renal function