Laboratory Medicine
Test Directory / EMA (eosin-5-maleimide) binding test
EMA (eosin-5-maleimide) binding test
EDTA
| Test | EMA (eosin-5-maleimide) binding test |
|---|---|
| Common Abbreviations | |
| Profile | |
| Clinical Indication | This assay is useful in the diagnosis of Hereditary Spherocytosis (HS). The results should be interpreted alongside a FBC and morphological assessment of a peripheral blood film. Eosin 5-Maleimide is a fluorescent dye which binds covalently to band 3 protein in the red cell membrane. Analysis by flow cytometry measures the fluorescence intensity of labelled intact red cells. Indication for requesting: Investigation of a suspected case of Hereditary Spherocytosis where the FBC result and morphology are indicative, or there is a family history, and other causes of haemolysis have been ruled out. |
| Specimen Type | Blood |
| Sample Type | EDTA |
| Minimum Volume | 1mL. The patient should not have received a transfusion in the last 3 months. 1 x 3 mL |
| Special Precautions | Please discuss with Consultant Haematologists in the first instance |
| Stability | 24 hrs. Samples must be received in the morning by the lab, Monday - Thursday, in order to dispatch to Manchester in time. Samples will be rejected by Manchester if >72 hours old. |
| Turnaround Time | 4 Days |
| Laboratory | Manchester Royal Infirmary Immunology Dept. |
| Reference Interval | Interpretation will be provided on the report. |
| Limitations | False positive results may occur for a wide spectrum of clinical conditions and rare red cell disorders unrelated to cytoskeleton defects e.g. Hereditary pyropoikilocytosis, Cryohydrocytosis, Congenital dyserythropoietic anaemia, South-East Asian ovalocytosis. Therefore caution is required when a positive test result for HS is not compatible with the clinical presentation and red cell morphology. |
| Additional Information | Examination of a blood film for the presence of spherocytes along with a clinical history is important in the evaluation of a reduced EMA binding test result. The presence of spherocytes and a reduced Eosin 5-Maleimide binding test result is suggestive of a diagnosis of Hereditary Spherocytosis. In some patients the test may not prove to be diagnostic and a diagnosis can only be made using other methods. |
