Urine Testing

Testing Urine

Unit 18:11

Urinalysis

Examination of urine Physical Chemical Microscopic

Physical Testing of Urine

Observing color, transparency & specific gravity

Color

Normal: shade of yellow Pale: dilute Dark yellow, orange: concentrated Cloudy red: hematuria Clear-red: hemoglobin Yellow or beer-brown: bilirubin

(bilirubinuria)

Transparency Normal: clear Cloudy: pus,

mucus Milky: fats

Specific Gravity

Normal: 1.005 to 1.030 Increased: dehydration, diabetes

mellitus Decreased: kidney disease,

diuretic, increased fluid intake

Odor

Normal: Faintly aromatic Ammonia: old sample Foul: infection Sweet: DM, ketones

Chemical Testing pH Protein Glucose Ketones

Bilirubin Urobilinogen Blood

Microscopic Testing Examine formed

elements in urine Cells Casts Crystals Amorphous debris

Which urine is best? Fresh, warm urine Within 1 hour of

collection Maybe

refrigerated if needed

Precautions Must use standard

precautions Gloves, possibly

mask, eyewear Discard urine in a

toilet Dispose of

specimen in infectious waste bag

Using Reagent Strips to Test Urine

Unit 18:12

Reagent Strips Firm plastic strip

with chemical reactants attached to the strip

Color change indicates presence of substance & amount of substance

Storage

Sensitive to light, heat, moisture Store in dry, cool, dark area Keep bottle closed

Precautions

Don’t touch chemical reactant pads

May lead to inaccurate results or injure the skin

pH

Measure of acidity or alkalinity of urine

Normal: 5.5 to 8.0 Affected by:

Diet Medications Kidney disease Starvation

Protein

Normal: none Proteinuria may indicate kidney

disease

Glucose

Normal: none May indicate Diabetes mellitus

Ketones

End product of fat metabolism Normal = none May indicate:

Diabetes mellitus Fasting, dieting High fat diet

Blood Normal = none May indicate:

Injury Infection Menstruation Kidney disease

Bilirubin Break down

product of hemoglobin

Normal = none May indicate:

Liver disease

Urobilinogen

Bilirubin converted by intestinal bacteria

Normal: small amounts May indicate:

Heart, spleen, liver or hemolytic disease

Spectrophotometers Automated strip

analyzer More accurate

than human eye

Refrigerated samples

Must be returned to room temperature

Time

Follow exact time for each chemical reaction

Measuring Specific Gravity

Unit 18:13

Specific Gravity

Density of a substance compared to the density of water

Normal: 1.005 to 1.030

Urinometer Urine in a cylinder

and calibrated float is placed in urine with a spinning motion

Urine collects at curved line, meniscus

Read of lower part of meniscus

Refractometer One drop of urine

placed on device & look through an eyepiece

Calibrate with water

Preparing Urine for Microscopic Examination

Unit 18:4

Urine Sediment

Solid materials suspended in urine

What urine?

Fresh, early morning first voided specimen preferable

Examine immediately Some elements disintegrate

Centrifuge Spin ~10-15 cc of

urine Solid materials

settle at the bottom

Preparation

Clear urine on top is poured off Leave behind 1 cc in bottom

Examine immediately

Drying occurs quickly & can distort substances

lpf and hpf

Low power field and high power field

Indicate amount seen in a field

RBCs Normal = none May indicate:

Kidney disease Bleeding in

urinary tract Menstruation

WBCs Normal = small

numbers May indicate:

infection

Bacteria Normal: none to

small amount Large amount

indicates infection

Other infectious agents Fungi, yeasts Parasites

Casts Formed in kidney

tubules during kidney damage

Normal = none

Crystals Dependent on

urine pH