Lab 41

Urinalysis

Urine

• 180L/day filtrate 1.8L/day urine• Sterile• Contains:

– Water (~ 95%)– Urea (from amino acids)– Creatinine (from muscle creatine phosphate)– Uric acid (From nucleic acids)– Urobilins (urochrome)– Electrolytes

General Characteristics of Normal Urine

Table 26–5

Urine – variable components

• pH = 6.0 normally– Can be amore acidic due to respiratory problems,

acidosis, uncontrolled diabetes, starvation and high protein diets

– Can be basic due to chronic renal failure, UTI, vegetarian diet

• Ketones in the urine (starvation, diabetes) give it an fruity smell

• Glucose in the urine may give is a sweet smell

Nitrogenous wastes

• Urea: breakdown of amino acids in the liver and other cells leads to the production of ammonium ion NH4

+ + CO2

urea

• Uric Acid: breakdown product of nucleic acids

• Creatinine: from muscle metabolism of creatine phosphate

Urine characteristics• Color• Turbidity• Smell• Density (specific

gravity) Contents:• Water• Chemicals:

– Urea – Na+, K+– Phosphate, sulfate ions– Creatinine – Uric acid– Urobilins

• Sometimes:– Glucose – Albumin (plasma protein)– Ketones– Hemoglobin– RBCs– Bilrubin– Nitrites– WBCs– Casts

Specific Gravity is a measure of urine concentration

Excessively concentrated urine can crystallize over time forming kidney stones

Today

• Get into groups

• In each group, one person can do an unknown pathological “urine” sample; others use your own urine sample

• Collect your sample – starting at midstream is best

• Note characteristics (color, turbidity, odor)

• Test specific gravity with urinometer – rinse and place in bleach when done

Today

• Test pH with pH paper (optional)• Test for Sulfates, Phosphates & Chlorides - all

chemical tests done in the test tubes provided.• Glucose with the Clinitest tablets.• Bilibubin with the the Ictotest.• Multistix test strips for leukocytes, nitrite,

urobilinogen, protein, blood, bilirubin, pH, specific gravity, and glucose (note the time differences among them)

• Centrifuge, stain and examine

Tests for Sulfates, Phosphates, Chlorides

• Sulfates – Measure 5ml of urine an put in test tube– Add a few drops dilute HCl– Add 2ml of 10% barium chloride– Precipitates indicate sulfates

• Phosphates– Place beaker ½ of water on hot plate and heat– Put 5ml urine in test tube with 3-4 drops nitric acid and 3ml

aluminum molybdate– Mix well with glass rod, then heat in bath– Yellow precipitate indicate phosphates

• Chlorides– To 5ml of urine in a test tube add several drops AgNO3– White precipitate indicated chlorides

Tests: Glucose, Bilirubin

• Glucose– Obtain the Clinitest tablets and color chart for

comparison– Put 5 drops of urine into a test tube– Rinse dropper and add 5 drops of water to the tube– Add Clintiest tablet, wait 15 sec, then compare color

to chart• Bilibubin

– Place one drop of urine in the center of the Ictotest mat with the the Ictotest.

– Place Ictitest tablet on top of urine drop– Add two drops of water directly to the tablet– Purple = bilirubin

Multistix

• Use Multistix test strips for leukocytes, nitrite, urobilinogen, protein, blood, bilirubin, pH, specific gravity, ketones, and glucose (note the time differences among them)

Staining

• DO THIS FIRST• Pour portion of sample into tube (10ml)• Give to me to centrifuge• When I return it, pour off the supernate• Take a sample of the pellet (sediment)• Put one drop on the slide with drop of stain• Cover slip examine and draw, comparing

to figure

Turn in

• Review Sheet 41

• Drawing of 2-3 interesting things seen in the urine

• Page 625 with results for real urine sample and pathological sample (record # at top of page)

• Due next Thurs