Evaluation of Dichlorophenolindophenol (DCIP) test for Haemoglobin E (Hb E) in normal red cell indices individuals

• Main Authors: Mohd. Yusoff, Mohd. Fauzi, Mohd Tohit, Eusni Rahayu, Hashim, Hafizah, Seman, Zainina
• Format: Article
• Language: English
• Published: Universiti Putra Malaysia 2021
• Online Access: http://psasir.upm.edu.my/id/eprint/97154/3/2021120708140602_MJMHS_0524.pdf; http://psasir.upm.edu.my/id/eprint/97154/; https://medic.upm.edu.my/upload/dokumen/2021120708140602_MJMHS_0524.pdf

The current cut-off value for thalassaemia screening is based on a mean corpuscular haemoglobin (MCH) level of less than 27 pg. Samples with MCH < 27 pg require additional confirmatory testing, while samples with MCH > 27 pg are considered normal. However, there is a possibility of missing some types of haemoglobinopathy such as haemoglobin (Hb) E trait, by using this cut-off value. This study aimed to evaluate the dichloroindophenol (DCIP) test for Hb E carriers within healthy individuals. Methods: In total, 200 leftover blood samples with normal full blood count (FBC) results and MCH ≥ 27 pg were collected from students who were involved in the thalassaemia screening program. Blood samples were screened for Hb E by the DCIP test and subjected to haemoglobin analysis using capillary electrophoresis (CE) and gel electrophoresis. Results: Of the 200 leftover blood samples with normal FBC indices, 10 were positive for the DCIP test of which 8 had Hb E trait and 2 had Hb Constant Spring. The DCIP test showed 100% sensitivity and 98.96% specificity with a 100% negative predictive value (NPV) and an 80.0 % positive predictive value (PPV). Conclusion: The DCIP test was an excellent screening tool that, when combined with FBC parameters can produce better results, particularly in areas with a high Hb E incidence.