['Abnormal methionine challenge test results cannot be explained by a deficiency in pyridoxal phosphate, folic acid, or cobalamin. The methionine challenge test is reliable for demonstrating hyperhomocysteinemia.', 'To research the status of pyridoxal phosphate, folic acid, and cobalamin as part of an examination for hyperhomocysteinemia and to establish their relationship to the results of methionine challenge tests in women, who were tested at least 3 months after they had ended a pregnancy which was complicated by preeclampsia or other vascular-related pregnancy complications.', 'In the Isala clinics in Zwolle, women with vascular-related complications of pregnancy were tested at least 3 months postpartum for hyperhomocysteinemia, by performing a methionine challenge test, as well as tests to measure their vitamin status. The diagnosis of hyperhomocysteinemia was made after two abnormal test results. The χ(2) test was used to compare the vitamin status of the group with normal results to those with an abnormal result of methionine challenge tests.', 'No statistically significant differences in the vitamin status were found between the group of women with an abnormal and the group with normal results of the methionine challenge tests.'] Is the reliability of methionine challenge test affected by a deficiency in pyridoxal phosphate , folic acid , or cobalamin?