PHYSICAL EXAMINATION OF URINE - FINAL

Urinalysis

The complete examination of urine involving physical, chemical, and microscopic tests.

Physical, Chemical, and Microscopic examination

The three stages of urinalysis.

Color and Clarity

In ancient times, medical decisions were based only on two urine characteristics. Name them.

Physical Examination

The stage of urinalysis that provides preliminary identification of conditions like glomerular bleeding or UTI.

Pathologic abnormality

This type of abnormality in urinalysis findings indicates a real disease condition.

Non-pathologic abnormality

This type of abnormality in urinalysis findings is harmless or temporary.

Clarity

The parameter of physical examination that refers to the transparency or turbidity of urine.

Specific Gravity

This parameter was once part of both physical and chemical examination but is now only done in chemical examination.

Odor

This parameter is not part of the routine urinalysis report.

Midstream Clean Catch Urine

The specimen required for physical examination of urine.

Color

One of the main parameters of physical examination that deals with the shade/appearance of urine.

White background

The recommended background color when examining urine specimens for color assessment.

Urine Specific Gravity

This factor causes urine to appear darker when increased, and paler when decreased, according to Strasinger’s rule.

Diabetes Mellitus

A condition where urine color appears pale despite increased specific gravity.

160–180 mg/dL

The renal threshold of glucose in mg/dL.

Polyphagia, Polydipsia, Polyuria

Name the 3 classic symptoms of Diabetes Mellitus that affect urine color.

Colorless to Black

The range of urine color from normal to abnormal extremes.

Urochrome

The yellow pigment of urine produced at a constant rate.

Urochrome

This pigment increases in amount during thyroid conditions and fasting.

Uroerythrin

The pigment that attaches to urates, producing a pink color in the urine sediment.

Uroerythrin

This pigment is more evident in refrigerated specimens due to precipitation of amorphous urates.

Urobilin

The oxidation product of urobilinogen that imparts an orange-brown color to old urine.

Colorless to Deep Yellow

Normal urine color ranges from ______ to ______.

Diabetes Mellitus (or Diabetes Insipidus)

A patient with pale yellow urine may be experiencing polyuria due to this endocrine condition.

Foam Test (shaking the specimen in a tube)

The physical test used to detect bilirubin in urine.

Proteins

Stable, white foam in urine is an indication of high concentration of what substance?

Pseudomonas infection

A green or blue-green urine color may be caused by this bacterial infection.

Myoglobin

A red urine color with ≥25 mg/dL of this pigment suggests muscle breakdown.

Methemoglobin

Brown/black urine caused by RBCs is due to their oxidation into what compound?

Klebsiella or Providencia

Purple staining of urine in catheter bags is often caused by which bacterial species?

Amitriptyline (Elavil)

This antidepressant drug causes urine to appear blue-green.

Levodopa (L-dopa)

Urine that turns red then brown in alkaline pH is commonly seen in patients treated with this Parkinson’s drug.

Rifampin

This anti-TB drug causes a bright orange-red urine color.

Riboflavin

This vitamin, often included in multivitamins, gives urine a bright yellow appearance.

Phenazopyridine (Pyridium)

A urinary analgesic that produces orange-red urine in acidic pH.

Phenol

Brown urine that may turn green on standing can be caused by poisoning with this chemical.

Indigo Carmine Dye

This dye, used in renal function tests and cystoscopy, produces blue urine.

Metronidazole (Flagyl)

Which drug can cause urine to darken and appear reddish-brown, especially with Trichomonas or amoeba infections?

Newspaper print

A traditional method of checking urine clarity involves reading through what object?

Nubecula

What is the term for a faint cloud that appears in urine after standing?

WBCs and Epithelial cells (also mucus)

Name two cellular components responsible for the formation of a nubecula.

Clear

Which urine clarity term describes urine that is transparent with no visible particulates?

RBCs and WBCs

Hazy urine allows newsprint to be read through the specimen. Name two possible causes.

Bacteria and Yeast (also trichomonads)

Cloudy urine that blurs print may be caused by microbes such as ______ and ______.

Turbid

Urine that is completely opaque (newsprint cannot be seen) is termed what?

Suspected rape case

The presence of sperm in urine samples from female minors must be reported because it may indicate what?

Milky

Which type of urine clarity may show precipitation or clot formation?

Fungal infection (e.g., Candida)

Turbid urine due to yeast may indicate what type of infection?

Uroerythrin

Amorphous urates produce a pink “brick dust” precipitate in acidic urine due to the presence of what pigment?

Phosphates and Carbonates

White precipitate in alkaline urine is commonly caused by amorphous ______ and ______.

Squamous epithelial cells and Mucus

Give two non-pathologic causes of urine turbidity often seen in female patients.

Pathologic

Presence of lipids in turbid urine is considered (pathologic / non-pathologic)?

1.002 – 1.035

What is the normal random urine SG range?

Chronic or End-stage Renal Disease

If SG is 1.010 consistently in a patient, what condition is suspected?

SG remains 1.010, same as plasma filtrate

What does “isosthenuric” mean?

Refractive Index (light velocity comparison: air vs solution)

What is the principle of refractometer?

0.004

How much should be subtracted for each g/dL of glucose in SG correction?

0.003

1.000

Calibration SG of distilled water

1.015 ± 0.001

1.022 ± 0.001

Calibration SG of 5% NaCl

1.034 ± 0.001

Calibration SG of 9% sucrose

Urinometer

Old instrument for measuring SG

10–15 mL

Volume required by urinometer

Subtract 0.001

Correction factor for every 3°C below calibration temp

Add 0.001

–0.003 per g/dL

Correction factor for protein

–0.004 per g/dL

Correction factor for glucose

Lower meniscus

Meniscus level read in urinometer

Corrected SG = 1.032

Example: 1.030 at 26°C (calibrated at 20°C)

Reagent strip method

Fastest method for SG

pKa change of polyelectrolyte

Principle used in reagent strip method

Bromothymol blue

Indicator dye commonly used

Add 0.005

Correction when pH ≥ 6.5

glucose, protein, radiographic contrast media

Reagent strip method is not affected by…

High protein concentration

What causes false positives in the reagent strip method?

Highly alkaline urine (>6.5)

What causes false negatives in the reagent strip method?

Buoyancy

What is the principle of the urinometry method?

Refractive Index

What is the principle of the refractometry method?

density (oscillation)

What is the principle of Harmonic Oscillation Densitometry?

Test with known +/– controls when opening a new bottle

What is the QC for reagent strips

45 seconds

What is the strip reading time for SG

Prism & cover

Part cleaned before using refractometer

Prevent sediments from settling, avoid false “clear” reporting

What is the reason for mixing specimen before exam

Adequate, consistent room lighting

What is the light condition requirement for the gross analysis of urine samples?