PT  - JOURNAL ARTICLE
AU  - J. Forshaw
AU  - Lilian Harwood
TI  - Diagnostic value of the serum folate assay
AID  - 10.1136/jcp.24.3.244
DP  - 1971 Apr 01
TA  - Journal of Clinical Pathology
PG  - 244--249
VI  - 24
IP  - 3
4099  - http://jcp.bmj.com/content/24/3/244.short
4100  - http://jcp.bmj.com/content/24/3/244.full
SO  - J Clin Pathol1971 Apr 01; 24
AB  - The diagnostic value of the serum folate assay has been assessed in 90 patients, each of whom had a macrocytic anaemia and a low serum vitamin B12 level. Twenty-nine (32%) patients were found to have anaemia due primarily to folate deficiency. The cause of the low serum vitamin B12 levels is uncertain in the 22 (25%) patients with normal or borderline vitamin B12 absorption. The effect of folic acid therapy was studied in four of these patients, and in each case the serum vitamin B12 rose slowly to a normal level. The serum folate was low in only four (7·5%) of the 54 patients with pernicious anaemia, and the levels rose to normal on treatment with vitamin B12 alone. A high serum folate occurred in eight (15%) pernicious anaemia patients. A normal serum folate indicated the diagnosis of pernicious anaemia or megaloblastic anaemia following partial gastrectomy. However, a normal serum folate and a very low vitamin B12 level was found in two patients with idiopathic steatorrhoea. It is concluded that the serum folate assay is a valuable routine test in patients who have a macrocytic anaemia and low serum vitamin B12. A low folate level makes the diagnosis of pernicious anaemia unlikely and is a strong indication for full investigation of small intestinal function.