Haemoglobin - Coated Charcoal for Estimation of Gastric Intrinsic Factor

Abstract

Vatn, M. H. Haemoglobin-coated charcoal for estimation of gastric intrinsic factor. Scand. J. Gastroent. 1973, 8, 755-760.

An examination of the different steps of the charcoal method is described, using haemoglobin as coating material. A within assay precision of 3.7 per cent, and a between assay precision of 4.5 per cent was achieved. An approximately linear relationship was found for the vitamin B₁₂-binding capacity and different amounts of gastric juice in the range of 20-80 per cent of the B₁₂ standard. The results of methodological investigations suggest that neutralized gastric juice should be incubated with antiserum for at least 2 minutes, and vitamin B₁₂ for 1 hour, at room temperature. The present report also indicates that the coated charcoal method is pH dependent, and unreliable for examination of IF-B₁₂ binding at extreme pH values. Comparison between haemoglobin- serum-, and dextran-coated charcoal showed that estimation of IF activity provided similar results with the three coating materials, and that the estimated unspecific B₁₂ binding activity was higher with dextran than with haemoglobin and serum.

Key-words::

• Charcoal
• dextran
• haemoglobin
• hydrogen ion concentration
• immunology
• intrinsic factor
• peptic degradation
• vitamin B₁₂