Abnormal results may include:

• Hyaline casts -- these casts are made of the protein itself. They are usually caused by dehydration, exercise, or diuretic medicines.
• Granular casts -- these casts include prominent granules and indicate an underlying kidney disease. However, they are non-specific and may be present with diverse kidney disorders.
• Fatty casts -- these result when fatty (lipid) material is incorporated into the cast from lipid-laden tubular cells. Fatty casts are seen in the condition of lipiduria (lipids in urine), usually as a complication of nephrotic syndrome.
• Red cell casts -- these signify bleeding into the tubule from the glomerulus. They are seen in many diseases affecting the glomerulus, such as IgA nephropathy, lupus nephritis, Goodpasture's syndrome , and Wegener's Granulomatosis. Red cell casts may degenerate and appear in the urine as reddish-brown, coarsely granular casts, called blood or hemoglobin casts.
• White blood cell (WBC) casts -- these are more common in interstitial cell kidney disease, such as interstitial inflammation, pyelonephritis, and parenchymal infection.
• Renal tubular epithelial cell casts -- these reflect damage to the tubules. They are seen in renal tubular necrosis (for example, caused by nephrotoxic drugs, heavy metal poisoning, or ethylene glycol), viral disease (such as CMV nephritis), and with transplant rejection.
• Waxy casts -- these casts are associated with advanced kidney disease and chronic kidney failure.

This test may also show:

• Acute nephritic syndrome
• Glomerulonephritis - chronic
• Glomerulonephritis - post-streptococcal
• Glomerulonephritis - rapidly progressive
• Complicated urinary tract infection
• Necrotizing vasculitis
• Rhabdomyolysis
• Primary amyloid
• Secondary amyloid
• Systemic lupus erythematosus

The best way to look for casts is to examine freshly voided urine, preferably the first morning urine sample.