AUBF_Midterms_Lab: Microscopic exam of urine

Standard centrifugation time and speed for urine sediment preparation

5 minutes at 400 RCF

Volume of urine remaining after decantation

0.5–1.0 mL

Purpose of agitation before slide preparation

To resuspend formed elements evenly

Volume placed on slide for examination

20 µL (0.02 mL)

Standard coverslip size used

22 × 22 mm

Minimum microscopic fields examined

At least 10 (low and high power fields)

Normal microscopic appearance of RBC

Non

Appearance of RBC in hypertonic urine

Crenated

Appearance of RBC in hypotonic urine

Ghost cells

Dysmorphic RBCs indicate

Glomerular membrane damage

RBC reporting format

Average number per 10 HPFs

Common RBC identification errors

Yeast cells, oil droplets, air bubbles

Urinalysis correlation for RBC

Urine color and reagent strip blood

RBC casts plus dysmorphic RBCs indicate

Glomerulonephritis

Crenated RBCs suggest what urine condition

Hypertonic urine

Ghost RBCs suggest what urine condition

Hypotonic urine

Average diameter of WBC in urine

About 12 µm

Most common WBC in urine sediment

Neutrophil

Characteristic nucleus of neutrophil

Multilobed

Glitter cells are associated with

Hypotonic urine

Mononuclear cells characteristic

Abundant cytoplasm

WBC reporting format

Average number per 10 HPFs

Common WBC identification error

Renal tubular epithelial cells

Reagent strip correlation for WBC

Leukocyte esterase

Additional WBC correlations

Nitrite, specific gravity, pH

WBC casts indicate

Pyelonephritis

Positive leukocyte esterase with WBCs suggests

Urinary tract infection

WBCs present but nitrite negative suggests

Non

Microscopic appearance of bacteria

Small spherical or rod

Bacteria reporting format

Few, moderate, or many per HPF

Bacteria identification error

Amorphous phosphates and urates

Bacteria should be correlated with presence of

WBCs

Bacteria urinalysis correlations

pH, nitrite, leukocyte esterase, WBCs

Rod

shaped bacteria with positive nitrite indicate

Bacteria without WBCs suggest

Contamination

Microscopic appearance of yeast

Oval refractile structures with buds or mycelia

Yeast reporting format

Few, moderate, or many per HPF

Yeast identification error

Amorphous phosphates and urates

Yeast with WBCs suggests

Fungal infection

Microscopic appearance of mucus

Low refractive threads

Mucus reporting format

Rare, few, moderate, or many per LPF

Mucus identification error

Hyaline casts

Mucus urinalysis correlation

None

Casts are reported per

Low power field (LPF)

Protein forming hyaline casts

Tamm-Horsfall protein (Uromodulin)

RBC cast indicates

Glomerular bleeding

WBC cast indicates

Renal infection

Epithelial cast indicates

Tubular damage

Fatty cast indicates

Nephrotic syndrome

Waxy cast indicates

Chronic renal disease

CaOx

Envelope shaped crystal

Rhomboid crystal

Uric acid

Yellow

brown granular crystal in acid urine

Granular crystal in alkaline urine

Amorphous phosphates

Wedge

shaped crystal

Thorny apple crystal

Ammonium biurate

Coffin

lid crystal

Round crystal with radial striations

Calcium carbonate

Crystal associated with ampicillin therapy

Ampicillin crystal

Crystal seen in liver disease

Bilirubin crystal

Flat rectangular crystal with notched corners

Cholesterol crystal

Hexagonal crystal

Cystine crystal

Yellow spherical crystal with concentric rings

Leucine crystal

Crystal associated with sulfa drugs

Sulfonamide crystal

Fine needle bundles in acid urine

Tyrosine crystal

Hexagonal crystals indicate

Cystinuria

UTI

Coffin-lid crystals in alkaline urine indicate

Tyrosine crystals suggest

Severe liver disease

Cholesterol crystals indicate

Nephrotic syndrome

Ammonium biurate crystals appear in

Alkaline urine