Snapshot A 22-year-old woman presents with dysuria, pyuria, and increased urinary frequency. She reports her symptoms began approximately 2 days prior to presentation. She has had similar symptoms 5 months ago. She is sexually active and uses condoms inconsistently. Physical examination is unremarkable. Urinalysis is positive for pyuria and bacteruria. Urine culture demonstrates ≥ 100,000 colony forming units (CFU) /mL. Introduction Process a fresh urine specimen is obtained and subsequently centrifuged the supernatant is placed in a separate tube a urine dipstick is placed in the supernatant to analyze for pH normal is between 5-6.5 clinical correlate urine pH >7.5 can suggest a urinary tract infection (UTI) secondary to urea-splitting microbe glucose clinical correlate urine glucose can be detected in the urine in poorly controlled diabetes mellitus ketones clinical correlate urine ketones can be seen in poorly controlled diabetes mellitus nitrite clinical correlate can be a reasonably good screening test for UTI heme clinical correlate typically indicative of blood in the urine however, the urine can be heme positive in the setting of intravascular hemolysis and rhabdomyolysis protein clinical correlate elevated protein in the urine can suggest a nephrotic syndrome specific gravity reflects the weight of a solution compared to the weight of distilled water the solution and distilled water must be of equal volume when the urine contains large solutes (e.g., glucose) the specific gravity increases urine osmolality measures the amount of dissolved particles per unit of water found in urine the sediment should be resuspended and then transferred to a slide for analysis urine casts these represent protein and cell precipitates generated within the tubular lumen red blood cells (RBCs) red cell morphology dysmorphic RBCs suggests glomerular bleeding round and uniform RBCs suggests extrarenal bleeding (e.g., ureter and bladder) white blood cells (WBCs) seeing WBCs in the urine is termed pyuria and suggests an infection or inflammatory process in the urinary tract neutrophils are more commonly seen eosinophiluria can be see in drug-induced acute intestitial nephritis epithelial cells crystals Urine Casts Casts Associated Conditions RBC casts Glomerulonephritis Vasculitis Malignant hypertension WBC casts Tubulointerstitial inflammation Acute pyelonephritis Transplant rejection Fatty casts Nephrotic syndrome "Maltese cross" sign Granular casts Acute tubular necrosis Waxy casts End-stage renal disease Chronic renal failure Hyaline casts Non-specific