Table 2

Importance of elements seen on direct microscopy of urine

White blood cellsUrinary tract infection or inflammation
(see causes of sterile pyuria (table 1))
Red blood cellsUrinary tract infection or inflammation
Calculi or neoplasia
EosinophilsAcute interstitial nephritis
Epithelial cellsContamination of specimen
HyalineNormal finding in concentrated urine
GranularRenal parenchymal disease (non-specific)
Red blood cellGlomerulonephritis, vasculitis
White blood cellInterstitial nephritis, pyelonephritis
Epithelial cellAcute tubular necrosis, interstitial nephritis, glomerulonephritis
CrystalsSeveral different types of crystals may develop in the urine including uric acid, calcium phosphate, calcium oxalate, cystine and sulphur. Their evaluation is outside the remit of the diagnostic microbiology laboratory