Usefulness of serum ferritin levels in the assessment of iron status in non-pregnant Zairean women of childbearing age.

We studied the usefulness of serum ferritin for the assessment of iron deficiency (ID) or ID anaemia (IDA) of 186 lactating and 27 non-lactating Zairean women (15-45 years old). Haemoglobin (Hb), serum iron (SI), total iron binding capacity (TIBC), and transferrin saturation (TS) were also measured. Participants were recruited in rural Bas-Zaire State in the summers of 1986 and 1989. Serum ferritin ranged from 10 to 360 micrograms l-1 (median 62 micrograms l-1) in lactating women and from 14.2 to 120 micrograms l-1 (median 40 micrograms l-1) in non-lactating women. While mean levels of serum ferritin and TS were within the normal range in both groups of women, those of Hb were below normal (< 12 g dl-1), partly due to inflammation. The prevalence of anaemia was 66% in lactating women and 70% in non-lactating women, and did not change with time. It was higher in women with inflammation than in those without inflammation. Although ID (ferritin < 12 micrograms l-1) was almost absent, after raising the cut-off point of ferritin to 50 micrograms l-1 in women with inflammation, it was present in 28.8% of lactating women and 52% of non-lactating women. While the prevalence of ID assessed by serum ferritin was significantly higher in lactating women studied in 1989 (40.5%) than in those studied in 1986 (13.5%), it was similar in both groups of non-lactating women. ID defined by TS < 16% was present in 41% of lactating women and 21% of non-lactating women. In the presence as well as absence of inflammation, the use of TS identified a higher percentage of lactating women with either ID or IDA than did the use of serum ferritin. We conclude that, in the studied population, unless inflammation is taken into consideration, serum ferritin has a limited value in the diagnosis of ID.