Lab Tests Reference Library

Urine pH measures the acidity or alkalinity of urine. It helps evaluate kidney stone risk, acid-base balance, and urinary tract infections. Alkaline urine may suggest UTI with urease-producing bacteria.

Proteinuria indicates kidney damage. Trace amounts may be normal or due to fever/exercise. Persistent proteinuria requires further evaluation with albumin/creatinine ratio. Associated with diabetic nephropathy, hypertensive kidney disease.

Glucose in urine (glucosuria) typically indicates blood glucose exceeding the renal threshold (~180 mg/dL). Seen in uncontrolled diabetes. Also occurs in renal glycosuria where glucose leaks at normal blood sugar levels.

Ketonuria indicates fat breakdown as an energy source. Present in diabetic ketoacidosis (DKA), starvation, low-carbohydrate diets, and prolonged vomiting. DKA is a medical emergency requiring urgent care.

Blood in urine (hematuria) can be gross (visible) or microscopic. Causes include kidney stones, UTI, glomerulonephritis, or bladder/kidney cancer. Any unexplained hematuria requires investigation.

Positive urine nitrites indicate bacterial infection. Gram-negative bacteria (E. coli, Klebsiella) convert dietary nitrates to nitrites. Combined with positive leukocytes, strongly suggests urinary tract infection (UTI).

White blood cells in urine (pyuria) indicate inflammation or infection of the urinary tract. Present in UTI, pyelonephritis, kidney stones, and interstitial nephritis. Combined with nitrites confirms bacterial UTI.

ACR is the preferred test to detect early diabetic kidney disease (microalbuminuria). It corrects for urine concentration. Persistently elevated ACR is an independent risk factor for cardiovascular events and kidney disease progression.

Specific gravity measures urine concentration. Low values suggest dilute urine (diabetes insipidus, excessive fluid intake, kidney disease). High values indicate concentrated urine (dehydration, SIADH, proteinuria).

24-hour urine protein quantifies daily protein excretion. It is the gold standard for evaluating nephrotic syndrome and monitoring kidney disease progression. >3.5 g/day defines nephrotic-range proteinuria.