Determination of functional iron deficiency status in haemodialysis patients in central South Africa.

INTRODUCTION: Functional iron deficiency (FID) is characterized by adequate body iron stores with an inadequate rate of iron delivery for erythropoiesis. In chronic kidney failure (CKD), iron availability is best assessed using the percentage of hypochromic red cells (%Hypo). The aim of our study was to determine the FID status of haemodialysis patients in central South Africa, using the %Hypo analyte and to evaluate the ability of the currently used biochemical tests, transferrin saturation (TSat) and serum ferritin to diagnose FID.

METHODS: For this study, 49 patients on haemodialysis were recruited. Haemoglobin (Hb), mean cell volume (MCV) and %Hypo were measured on the Advia 2120i. Biochemical analytes (serum ferritin, TSat) and C-reactive protein (CRP) levels were also recorded.

RESULTS: Of the 49 participants, 21 (42.9%) were diagnosed with FID (%Hypo >6%). A large number of patients (91.8%) were anaemic. The TSat demonstrated poor sensitivity and specificity for diagnosing FID compared with %Hypo. The use of %Hypo (rather than TSat) to guide intravenous iron use spared 16 patients the potential harmful effects thereof.

CONCLUSION: Using %Hypo as a single analyte to diagnose FID will lead to more appropriate use of limited resources and a reduction in treatment-related complications.