Quantification of ineffective erythropoiesis in megaloblastic anaemia by determination of endogenous production of 14CO after administration of glycine-2-14C.

The determination of the early peak of 14CO production that results from haem turnover after administration of glycine-2-14C was studied in patients with pernicious anaemia. The accuracy of this technique in measuring ineffective erythropoiesis was assessed by comparison with other measurements of the severity of the disease. 6 patients were studied before specific treatment and 2 of these also after treatment. The endogenous production of 14 CO was calculated from determinations of the production of CO by a rebreathing technique and of the specific activity of CO washed out from the body CO store by oxygen breathing. The early labelled peak was increased 7-39 times compared to that in healthy control subjects and represented 35-86% of the total production of 14CO as compared to 13% in controls. The early labelled peak was significantly correlated to the Hb concentration, mean red cell volume and endogenous production of CO. 2 patients, twice examined, showed a moderately increased early labelled peak also after specific treatment. This was attributed to persistence of some ineffective erythropoiesis in 1 patient and possibly increased hepatic haem turnover in the other. The magnitude of the early labelled peak and the maximal activity of 14CO found in the samples of CO collected from the body CO store were significantly correlated. In conclusion, with the present method the early peak of 14CO reflected the ineffective erythropoiesis in patients with pernicious anaemia. The early labelled peak could be predicted from the maximal activity of 14CO found in the samples of CO washed out from the body CO store.