Importance of elements seen on direct microscopy of urine
| Elements | Importance |
|---|---|
| Cells | |
| White blood cells | Urinary tract infection or inflammation |
| (see causes of sterile pyuria (table 1)) | |
| Red blood cells | Urinary tract infection or inflammation |
| Calculi or neoplasia | |
| Eosinophils | Acute interstitial nephritis |
| Epithelial cells | Contamination of specimen |
| Casts | |
| Hyaline | Normal finding in concentrated urine |
| Granular | Renal parenchymal disease (non-specific) |
| Red blood cell | Glomerulonephritis, vasculitis |
| White blood cell | Interstitial nephritis, pyelonephritis |
| Epithelial cell | Acute tubular necrosis, interstitial nephritis, glomerulonephritis |
| Crystals | Several 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 |