GPT and kidney disorder: For example, in the absence of liver or bone disease, a low alkaline phosphatase (ALP) level suggests zinc deficiency; a serum level of aspartate aminotransferase (AST) > alanine aminotransferase (ALT) indicates vitamin B6 deficiency; an increase in mean corpuscular volume (MCV) with low ferritin means weakness of cell membranes; and a reduction in blood urea nitrogen (BUN) without kidney disease means a low protein intake [1].