Abstract
Background
The two most frequently encountered microcytic hypochromic anemias are iron deficiency anemia (IDA) and β-thalassemia trait (β-TT) which need relatively expensive laboratory tests to be differentiated.
Objectives
This study aims at evaluating the diagnostic utility of different discrimination formulas derived from red blood cell indices from complete blood count in the differentiation of β-TT from IDA.
Subjects and Methods
This study was conducted on 140 subjects; 40 healthy individuals and 100 patients (60 IDA and 40 β-TT) recruited from outpatient clinics of Ain Shams University Hospitals. They were 45 males and 95 females (M: F 1:2.1), their ages ranged from 19 to 63 years. Patients were subjected to measurement of CBC, iron profile, Hb electrophoresis and HPLC and calculation of RBC indices- derived formulas.
Results
Comparative studies of different formulas among the studied group shows that England and Fraser (E & F), MDHL, MCHD, MCI and Zaghloul 2 can significantly differentiate between β-TT patients and IDA patients (P was 0.009, 0.008, 0, 0.001 and 0.050 respectively). Evaluation of diagnostic performance (efficacy) of the studied RBCs formulas showed that Zaghloul 2 is the best index in discriminating β-TT from IDA at cut off 66.61 with specificity (97.5%), sensitivity (76.7%) and diagnostic efficacy (85%). This was followed by MCI at cut off 22.73 with specificity (57.5%), sensitivity (85.0%) and diagnostic efficacy (74. %). Then they are followed by MDHL at cut off 1.487 with specificity (50.0%), sensitivity (86.7%) and diagnostic efficacy (72.0), then England and Fraser with cut off 8.9 with specificity (50.0%), sensitivity (80.0%) and diagnostic efficacy (68.0%), and lastly MCHD with cut off 0.296 with specificity (72.5%), sensitivity (61.7%) and diagnostic efficacy (66.0%). Values above these cut off levels indicate β-TT whereas values below these levels indicate IDA except for E&F formula where <8.9 cut off indicate β-TT and >8.9 indicate IDA.
Conclusion
Zaghloul 2 formula showed the highest efficacy in the differentiation of β-TT from IDA (85%) followed by MCI (74%) and MDHL (72%) then England and Fraser (68%) and lastly MCHD (66%). They can be used for screening in big population, being simple and inexpensive, and then followed by the usual confirmatory tests. Their real use comes in rural areas and primary care facilities where only red blood cell indices are handy. They can be calculated and the cases can be referred to secondary health care to take the confirmatory tests for diagnosis.
Introduction of new formulas and evaluation of the previous red blood cell indices and formulas in the differentiation between beta thalassemia trait and iron deficiency anemia in the Makkah region