A comparative analysis between NAT and chemiluminescence in detection of transfusion transmitted viruses in two main university blood transfusion centers

Introduction

Although blood transfusion has saved millions of lives all over the world, transfusion transmitted infections (TTIs) still represent a major hazard to blood recipients. The four major TTIs are Hepatitis B virus (HBV), Hepatitis C virus (HCV), Human immunodeficiency virus (HIV), and Treponema pallidum (TP)^1,3.

According to the World Health Organization (WHO) 2021⁴ report, about 118.5 million blood donations were made (either whole blood or apheresis donations). The blood units were collected from voluntary, family, and paid donations. There are about 296, 58.0, and 39.0 million persons infected by HBV, HCV, and HIV respectively and the prevalence of such viruses in blood donors ranged from (high-income-low-income countries) 0.02 to 6.02%, 0.007 to 1.67%, and 0.002 to 1.6%, respectively. WHO planned to eliminate TTIs by screening blood donations in a quality-based manner and targeted to be zero risk in 2030^4,5.

The starting point for safe blood supply is the regular voluntary donations which represent 82.8% globally (about 95.6% in high-income countries versus 62.8% in low-income countries). The least risk of TTIs is associated with repeat voluntary donations and the risk can be reduced by systematic screening and testing for TTI markers. The use of standard techniques and active participation in external quality assessment are very crucial in this issue^{4, 5–6}.

The CLIA uses a chemical or enzymatic reaction to measure the absolute concentration of pathogen antibody or antigen in blood sample (i.e. measures the immune response of donors to viruses) by measuring the luminescence intensity. The NAT detects directly the nucleic acid of viruses by molecular biology technique (i.e. amplify targeted regions of viral nucleic acid before appearance of viral antigen or antibody). Therefore, the sensitivity and specificity of NAT are higher than those of CLIA, and the window between infection and detection of viruses by NAT is shorter than CLIA^7,8 The CLIA advantages include short time assay, low sample cost, high throughput, and simple equipment and technique. The NAT advantages include minimizing the risk of contamination, identifying different even emerging new viruses, and with a significant impact on blood safety (i.e. reduces the risk of TTIs from these viruses). However, NAT has some limitations such as pool assay which may need to reassess samples when...