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An "on the spot" test for targeted screening in index families of thalassaemia
Muhammad Sajid Yazdani1, Suhaib Ahmed
1Combined Military Hospital, Sargodha.
Insights
The One Tube Osmotic Fragility Test (OTOFT) effectively screens rural families for thalassaemia trait and iron deficiency. This simple, cost-effective method aids in early detection within at-risk populations.
Area of Science:
- Hematology
- Public Health
- Diagnostic Testing
Background:
- Thalassaemia is a significant genetic disorder, particularly in rural populations.
- Early screening is crucial for managing and preventing the transmission of thalassaemia major.
- Accessible and cost-effective diagnostic tools are needed for remote areas.
Purpose of the Study:
- To evaluate the One Tube Osmotic Fragility Test (OTOFT) as a field screening tool.
- To assess OTOFT's utility for families with a history of thalassaemia.
- To determine the test's accuracy in identifying thalassaemia trait and iron deficiency.
Main Methods:
- An observational cross-sectional study was conducted.
- Included members of families with a history of thalassaemia major from rural Pakistan.
- OTOFT performed using finger prick blood and 0.36% saline; results read visually.
Main Results:
- OTOFT was positive in 79% (135/171) of subjects.
- Of positive cases, 45% had thalassaemia trait and 39% had iron deficiency.
- OTOFT negative subjects showed a low incidence of thalassaemia trait (false negatives).
Conclusions:
- OTOFT is a simple, cost-effective field test for screening families with thalassaemia history.
- A positive OTOFT is sensitive for detecting thalassaemia trait or iron deficiency.
- OTOFT negative individuals can likely be excluded from further thalassaemia testing.
Objective:
To assess the usefulness of One Tube Osmotic Fragility Test (OTOFT) for "on the spot" screening of rural families with history of thalassaemia.
Methods:
It was an "observational cross-sectional" study conducted at Pathology Department of PNS Shifa Hospital, Karachi and included all available members of three families from the rural district (Badin) in Pakistan with history of at least one child with thalassaemia major. One drop of finger prick blood was added to 5 ml of 0.36% saline in a test tube (diameter 2cm). The results were read after 5-10 minutes by visualizing a written material through the contents of the test tube. In addition, samples were also collected for blood counts, Hb electrophoresis and serum ferritin.
Results:
OTOFT was positive in 135/171 (79%) subjects. In the 135 positives, subsequent investigations showed that 61 (45%) had thalassaemia trait, 52 (39%) had iron deficiency and 22 (16%) had neither of the two and were considered false positive. In the 35 OTOFT negative subjects none had thalassaemia trait while only one had iron deficiency (false negative).
Conclusions:
OTOFT is a simple and cost effective test which can be used in the field for screening index families with thalassaemia. While a positive test is sensitive for detection of thalassaemia or iron deficiency an OTOFT negative individual may be excluded from further testing for thalassaemia.
