Serial sections of formalin fixed paraffin embedded tissue are medically necessary, as are multiple slides (levels) stained with hematoxylin & eosin (H&E), PAS, trichrome, and silver. Multiple slides for each stain are needed to evaluate the different parts of the kidney: glomeruli, tubules, interstitium, and vasculature. Two standard H&E stained slides provide evaluation of all parts of the renal parenchyma. Two PAS stained slides highlight basement membranes of glomeruli, tubules, and vessels, and assist in evaluation of tubulitis in renal allografts. Two trichrome stained slides allow evaluation of deposits in glomeruli and interstitial fibrosis. Two silver stained slides highlight basement membranes for analysis of irregularities, thickening, or duplication.