Single Tube Osmotic Fragility Test: a Sensitive and Specific Test for Screening of Microcytosis

Aim and Objective: To evaluate usefulness of Single Tube Osmotic Fragility Test (SOFT) for detection of microcytosis and its further application for thalassemia trait screening. Background: Iron deficiency and thalassemia are common causes of microcytic anaemia in Pakistan. Easy microcytosis screening is necessary at a low resourced country like Pakistan, so that further investigations specially for thalassemia may be ordered. Thalassemia is one of the commonest genetic disorders of Pakistan that has both medical and social implication. Materials and Methods:A total of 387 students belonging to four different colleges of Gulshan-e-Hadid, were included in study. SOFT was performed on all 387 participants using 0.36% saline. Haemoglobin (Hb), Mean Corpuscular Volume (MCV) and Mean Corpuscular Haemglobin (MCH) was estimated in all individuals using Sysmexhaematology counter. Results: SOFT was positive in 26.87% of study population. Sensitivity and specificity of SOFT was found to be 93.94% and 96.18% for detection of microcytosis. Its positive and negative predictive values were 89.42% and 97.88% respectively. SOFT positive and negative groups showed statistically significant difference in Hb, MCV and MCH. Conclusion: SOFT can be used cost effectively for microcytosis screening. Its results can target individuals to be investigated for thalassemia.