Patent ID: 7846672

Claim:
A method for detecting the affinity of a folate receptor (FR) autoantibody in a subject, comprising: a. obtaining from a subject a biological sample suspected of comprising a FR autoantibody; b. providing an affinity matrix comprising apoFR; c. acidifying the biological sample; d. removing any unbound folic acid from the biological sample; e. contacting the affinity matrix with the biological sample under conditions suitable for forming an autoantibody-apoFR complex; f. dissociating and removing from the affinity matrix any apoFR-bound autoantibody; g. measuring the autoantibody's affinity for apoFR; and h. determining whether or not the dissociated autoantibody that was removed from the affinity matrix has an effect on folate uptake, wherein a value of about 10 10 L/mole for an autoantibody's affinity for apoFR indicates a high affinity and a value of about 10 6 L/mole for an autoantibody's affinity for apoFR indicates a low affinity.