Limited Dynamic Range of a New Assay for Serum Folate

Limited dynamic range of a new assay for serum folate.

To the Editor: Recently, several new nonisotopic protein-binding folate assays have become available. We have studied the AxSYM folate assay (Abbott Laboratories , Abbott Park, IL), in which folate is quantified by measurement of unoccupied binding sites on the folate-binding protein (1). The cali-brators for the assay cover the range 0 – 45 nmol/L. In the absence of an internationally accepted...

Dried-serum spot assay for folate.

Diagnostic value of the serum folate assay.

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 B(12) level. Twenty-nine (32%) patients were found to have anaemia due primarily to folate deficiency. The cause of the low serum vitamin B(12) levels is uncertain in the 22 (25%) patients with normal or borderline vitamin B(12) absorption. The effect of...

Lactobacillus case assay of serum folate

The Lactobacillus casei response to folate is normally estimated by measuring the culture turbidity after 16 to 20 hours' incubation. Streeter and O'Neill (1969) found that cultures containing serum grew more rapidly than similar cultures containing folic acid (PteGlu) unless grown into the stationary phase (44 hours). Others, however, have reported comparable results from 20and 44-hour assays ...

Radioisotopic assay for measurement of serum folate levels.

A radioisotopic assay is reported that 4 hr and can be run in unlimited quanaccurately measures an almost identical tity. This raclioassay should simplify diserum folate to that measured by Lactoagnosis of folate deficiency and be parbacillus casei and can separate low, ticularly useful in patients receiving borderline, and normal folate levels. This antibiotics and folate antagonists, where as...