An Evaluation of Microcytic Red Blood Cell Disorders in Patients Reporting to a Tertiary Care Centre in the Cook Islands

Abstract

Objective: Anaemia is a medical condition characterised by reduced levels of red blood cells (RBCs) and haemoglobin (Hb) in the blood. It is a relatively common condition which appears in many population health reports. The main objective of this study was to obtain an evaluation of microcytic RBC disorders in the Cook Islands population. This evaluation was assessed from the results of patient’s laboratory full blood count (FBC) tests at the Rarotonga Hospital Laboratory (RHL) (the national laboratory for the Cook Islands), using their standardised patient reference ranges. This study is of interest due to the lack of existing published studies based on microcytic anaemias in the local Cook Islands population. It is suspected that the cause of anaemia may be overlooked or misdiagnosed in this group, especially in the case of thalassaemia/haemoglobinopathies and iron deficiency anaemia (IDA) It is important to evaluate the prevalence of microcytic RBC disorders in the population to enable appropriate health care interventions and the provision of a suitable diagnostic service to support these interventions.

Methods: An audit was performed on 874 FBC results with low MCV (mean cell volume) and/or low MCH (mean cell haemoglobin) values. Mentzer Index (MI) and a web-based tool were applied to differentiate between IDA and thalassaemia as possible causes of microcytic anaemia. Where available, serum ferritin, CRP and alpha thalassaemia results were included in the evaluation of individual cases.

Results: Of the 874 patient FBC results, the MI suggested IDA in 646 (74%) individuals and thalassaemia in 225 (26%) individuals. Of the IDA estimates, 485 (80.6%) were females and 142 (59.2%) males. Thalassaemia estimates were more common among males, (40.4%) compared to females (19.1%). Part of the results includes the observation that most cases with microcytosis and/or hypochromia were not investigated according to best practice guidelines of my study.

Conclusion: This study has provided a preliminary evaluation of microcytic red cell disorders in the Cook Islands population presenting to RHL. It raises the likelihood that a significant number of cases of thalassaemia/haemoglobinopathy may be present in the population. A clear guideline for the investigation of microcytosis and hypochromia should be implemented to avoid missing or misdiagnosing patients with these FBC results. In addition, RHL should implement investigative protocols for thalassaemia/haemoglobinopathy. Additionally, thalassaemia/haemoglobinopathy prenatal screening should be included as part of the antenatal screening of pregnant mothers.