Samples containing EDTA, fluoride, oxalate, or citrate should not be used. Magnesium, at levels less than 5 mg/dL, does not interfere in this methodology. Hemoglobin, at levels less than 500 mg/dL (+4), will not produce significant bias. Positive or negative interference may be obtained from patients diagnosed as having plasma cell dyscrasiasand lymphoreticular malignancies associated with abnormal immunoglobulin synthesis,such as multiple myeloma, Waldenström's macroglobulinemia, or heavy chain disease. Lipemic samples should be ultra-centrifuged and the analysis performed on the infranate. |
