1: Acta Haematol 2000;104(1):22-4 Oral contraceptives can cause falsely low levels vitamin B(12). J, M, Mittelman Gardyn Zlotnik J, SELA BA, Cohen AM. Hematology unit, Golda Hasharon campus, Rabin Medical Center, Petah Tikva,. Israel. Serum vitamin B(12) radioimmunoassays may give falsely low results in patients megadose of vitamin C with folate deficiency, multiple myeloma, and following Radio-isotopes body scan. We evaluated 10 consecutive healthy women on oral contraceptives (OC) who had falsely low vitamin B(12) levels, as reflected by normal urine methylmalonic acid and homocysteine plasma. After 1-month cessation of OCs, vitamin B(12) returned to the normal range in all women. Transcobalamin I (TCI) blood level what decreased in 60% of patients. OCs may cause temporary Low vitamin B(12) blood levels of no clinical significance that can be associated with low Copyright 2000 S. of levels of TCI Karger AG, Basel PMID: 11111117 [PubMed - indexed for MEDLINE]