Abstract
The effects of varying the method of preparation of haemolysates on the measurement of red cell folate concentration were investigated using the Simultrac kit. The concentration of ascorbic acid did not have any significant effect on the assayed concentrations of folate, but lower concentrations were obtained when the incubation time was increased. Folate was stable for 14 days in cells when they were stored at 4 degrees C and for seven days at -25 degrees C, but instability was increased by storage in ascorbic acid, by the use of stored (4 degrees C) ascorbic acid, and by preparing the haemolysates by freeze-thaw cycling. It is recommended that haemolysates should be diluted in fresh ascorbic acid, at a concentration of 10 g/l, incubated for 60 minutes in the dark and stored at -20 degrees/25 degrees C before being assayed.
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Selected References
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- Bain B. J., Wickramasinghe S. N., Broom G. N., Litwinczuk R. A., Sims J. Assessment of the value of a competitive protein binding radioassay of folic acid in the detection of folic acid deficiency. J Clin Pathol. 1984 Aug;37(8):888–894. doi: 10.1136/jcp.37.8.888. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Bird O. D., McGlohon V. M., Vaitkus J. W. Naturally occurring folates in the blood and liver of the rat. Anal Biochem. 1965 Jul;12(1):18–35. doi: 10.1016/0003-2697(65)90138-7. [DOI] [PubMed] [Google Scholar]
- Gilois C. R., Dunbar D. R. Measurement of low serum and red cell folate levels: a comparison of analytical methods. Med Lab Sci. 1987 Jan;44(1):33–40. [PubMed] [Google Scholar]
- Givas J. K., Gutcho S. pH dependence of the binding of folates to milk binder in radioassay of folates. Clin Chem. 1975 Mar;21(3):427–428. [PubMed] [Google Scholar]
- HERBERT V., ZALUSKY R. Interrelations of vitamin B12 and folic acid metabolism: folic acid clearance studies. J Clin Invest. 1962 Jun;41:1263–1276. doi: 10.1172/JCI104589. [DOI] [PMC free article] [PubMed] [Google Scholar]
- IWAI K., LUTTNER P. M., TOENNIES G. BLOOD FOLIC ACID STUDIES. VII. PURIFICATION AND PROPERTIES OF THE FOLIC ACID PRECURSORS OF HUMAN ERYTHROCYTES. J Biol Chem. 1964 Jul;239:2365–2369. [PubMed] [Google Scholar]
- Omer A. Factors influencing the release of assayable folate from erythrocytes. J Clin Pathol. 1969 Mar;22(2):217–221. doi: 10.1136/jcp.22.2.217. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Rothenberg S. P., Da Costa M. Letter: Measurement of red cell folate levels. Br J Haematol. 1975 Jan;29(1):189–190. doi: 10.1111/j.1365-2141.1975.tb01812.x. [DOI] [PubMed] [Google Scholar]
- Rothenberg S. P., da Costa M., Lawson J., Rosenberg Z. The determination of erythrocyte folate concentration using a two-phase ligand-binding radioassay. Blood. 1974 Mar;43(3):437–443. [PubMed] [Google Scholar]
- Schreiber C., Waxman S. Measurement of red cell folate levels by 3H-pteroylglutamic acid (3H-PteGlu) radioassay. Br J Haematol. 1974 Aug;27(4):551–558. doi: 10.1111/j.1365-2141.1974.tb06620.x. [DOI] [PubMed] [Google Scholar]
- Shane B., Tamura T., Stokstad E. L. Folate assay: a comparison of radioassay and microbiological methods. Clin Chim Acta. 1980 Jan 1;100(1):13–19. doi: 10.1016/0009-8981(80)90180-1. [DOI] [PubMed] [Google Scholar]
- TOENNIES G., PHILLIPS P. M. Blood folic acid studies. V. Resolution of precursor and enzyme fractions of the blood folic acid system. J Biol Chem. 1959 Sep;234:2369–2372. [PubMed] [Google Scholar]
