Article Text

PDF

Microbiological assay of folic acid activity in human serum
  1. G. H. Spray
  1. Nuffield Department of Clinical Medicine, Radcliffe Infirmary, Oxford

    Abstract

    A method is described for the microbiological assay of folic acid activity in serum with Lactobacillus casei as test organism and a modified medium in which the organism gives a greater growth response than in media previously detailed. The results of experiments carried out to validate the use of this medium are shown.

    In 94 control subjects levels of folic acid activity in the serum ranged from 2· to 28 mμg./ml. (mean 7·8). The values in nine out of 10 patients with megaloblastic anaemia due to deficiency of folic acid were 1·0 mμg./ml. or less and one result was 2·0 mμg./ml. In six patients with megaloblastic anaemia associated with pregnancy the results ranged from 0·7 to 4·0 mμg./ml., and in untreated pernicious anaemia 28 out of 31 results were within or above the control range and three values were just below the lower limit of normal.

    Statistics from Altmetric.com

    Request permissions

    If you wish to reuse any or all of this article please use the link below which will take you to the Copyright Clearance Center’s RightsLink service. You will be able to get a quick price and instant permission to reuse the content in many different ways.