Provided is an isolated and purified DNA molecule comprising the coding region of a PCFT cDNA. Also provided is a segment of the above DNA molecule, capable of serving as a primer for amplifying at least a portion of the DNA molecule. Additionally provided is a pair of the above segments that can be used together as forward and reverse PCR primers for amplifying at least a portion of the above DNA molecule. Further provided is an isolated and purified human PCFT protein. Also provided is a method of evaluating the ability of a human to undergo intestinal folate absorption.