Is analysis of the reticulocyte haemoglobin equivalent a useful test for the diagnosis of iron deficiency anaemia in geriatric patients?

BACKGROUND: Iron deficiency anaemia (IDA) and anaemia of chronic disease (ACD) are common in elderly patients but there are no standard diagnostic criteria. The reticulocyte haemoglobin equivalent (Ret-He) is routinely measured by modern automated blood analysers and is an early indicator of iron deficiency. The aim of this study was to investigate whether the Ret-He level as calculated by the Sysmex XE-5000 automated blood analyser is a useful parameter for the diagnosis of IDA in a geriatric hospitalized population.
METHODS: In a prospective study, blood samples were collected in 26 geriatric patients with IDA and 111 patients with ACD diagnosed according to generally accepted laboratory and clinical criteria. A blood count including Ret-He, mean corpuscular volume (MCV), mean corpuscular haemoglobin (MCH), mean corpuscular haemoglobin concentration (MCHC) and standard iron parameters was performed in each patient.
RESULTS: Haemoglobin, Ret-He, MCV, MCH and MCHC levels were all significantly lower in IDA as compared to ACD patients. However, the area under the curve (AUC) was greater for MCH (0.87, 95% CI 0.78-0.95) and MCHC (0.86, 95% CI 0.76-0.96) then for Ret-He (0.828, 95% CI 0.73-0.93) and MCV (0.80, 95% CI 0.68-0.91). A Ret-He cut-off value of 26 pg had a sensitivity and specificity based on its optimal combination of 85% and 69% respectively.
CONCLUSION: Analysis of Ret-He does not perform better than the classical red cell indices such as MCH and MCHC in differentiating IDA and ACD in geriatric patients.