ABSTRACT
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.
Subject(s)
Anemia, Hypochromic/diagnosis , Hematologic Tests/methods , Hemoglobins/analysis , Iron Deficiencies , Kidney Failure, Chronic/blood , Transferrin/analysis , Adult , Anemia, Hypochromic/blood , Anemia, Iron-Deficiency/blood , Anemia, Iron-Deficiency/diagnosis , Erythrocytes/chemistry , Ferritins/blood , Humans , Iron/blood , Middle Aged , Renal Dialysis/adverse effects , Sensitivity and Specificity , South AfricaABSTRACT
INTRODUCTION: Physiological changes during pregnancy affect routine tests for iron deficiency. The reticulocyte haemoglobin equivalent (RET-He) and serum-soluble transferrin receptor (sTfR) assay are newer diagnostic parameters for the detection of iron deficiency, combined in the Thomas diagnostic plot. We used this plot to determine the iron status of pregnant women presenting for their first visit to an antenatal clinic in Bloemfontein, South Africa. METHODS: Routine laboratory tests (serum ferritin, full blood count and C-reactive protein) and RET-He and sTfR were performed. The iron status was determined using the Thomas plot. RESULTS: For this study, 103 pregnant women were recruited. According to the Thomas plot, 72.8% of the participants had normal iron stores and erythropoiesis. Iron-deficient erythropoiesis was detected in 12.6%. A third of participants were anaemic. Serum ferritin showed excellent sensitivity but poor specificity for detecting depleted iron stores. HIV status had no influence on the iron status of the participants. CONCLUSION: Our findings reiterate that causes other than iron deficiency should be considered in anaemic individuals. When compared with the Thomas plot, a low serum ferritin is a sensitive but nonspecific indicator of iron deficiency. The Thomas plot may provide useful information to identify pregnant individuals in whom haematologic parameters indicate limited iron availability for erythropoiesis.
