Urinalysis and Renal Function Overview

Vocabulary flashcards covering key terms and definitions related to urinalysis, abnormal urine constituents, and renal function tests.

Urinalysis

Laboratory examination of a urine sample to assess physical and chemical characteristics and detect abnormal constituents.

Normal Urine Volume

About 1–2 L excreted in 24 h; at least 0.5 L daily is required to remove wastes effectively.

Turbidity

Degree of cloudiness of urine; fresh urine should be clear, while cloudiness may indicate bacterial growth or infection.

Urinoid

The mildly aromatic normal odor of freshly voided urine.

Specific Gravity (Urine)

Density of urine relative to water (1.0); normally slightly higher due to dissolved solutes.

Albuminuria

Presence of albumin in urine, signaling filtration membrane damage or hypertension.

Glucosuria

Detectable glucose in urine, usually indicating diabetes mellitus.

Hematuria

Red blood cells in urine; associated with infections, stones, tumors, or kidney disease.

Ketonuria

Elevated ketone bodies in urine, common with diabetes, starvation, or low-carbohydrate diets.

Bilirubinuria

Bilirubin detected in urine, often reflecting liver disorders such as hepatitis or bile obstruction.

Urobilinogenuria

Excess urobilinogen in urine, suggesting liver disease or excessive hemolysis.

Casts

Microscopic cylindrical masses formed in renal tubules; their presence in urine indicates tubular pathology.

Microbes (Urine)

Bacteria, yeast, or protozoa in urine, evidencing a urinary tract infection.

Blood Urea Nitrogen (BUN)

Concentration of urea in blood; rises when glomerular filtration decreases.

Creatinine (Plasma)

Waste from muscle creatine phosphate breakdown; elevated blood levels imply impaired renal excretion.

Renal Plasma Clearance

Volume of plasma cleared of a substance per minute (ml/min); calculated as U × V ÷ P to assess kidney function.

Glomerular Filtration Rate (GFR)

Rate at which plasma is filtered in the glomeruli—about 125 ml/min in healthy adults.

Inulin Clearance Test

IV test using inulin, a non-reabsorbed/non-secreted polysaccharide, to measure true GFR.

Estimated GFR (eGFR)

Clinical approximation of GFR derived from creatinine clearance values (≈120–140 ml/min).

Ketone Bodies

Acetoacetate, β-hydroxybutyrate, and acetone produced during fat metabolism; give urine a fruity odor when elevated.

Methyl Mercaptan

Sulfur compound produced after asparagus digestion that imparts a distinctive urine odor in certain individuals.

U (Urine Concentration)

Variable representing a substance’s concentration in urine in clearance calculations.

V (Urine Flow Rate)

Variable representing the rate of urine formation (ml/min), often measured via 24-h collection.

P (Plasma Concentration)

Variable representing a substance’s concentration in plasma for renal clearance calculations.