Simple Blood Test Devised for Hepatitis B

Viral hepatitis is a major global health problem, and estimates suggest that hepatitis B was responsible for about half of the 1.45 million viral hepatitis-related deaths that occurred worldwide in 2013.

A simple inexpensive blood test has been devised that could be used widely in low-income and middle-income countries (LMICs) to help determine which patients with hepatitis B require immediate treatment. The affordable test is based on measurements of hepatitis B virus e antigen (HBeAg), and levels of the liver enzyme alanine aminotransferase (ALT), to generate a diagnostic score.

An international team of scientists led by the Institute Pasteur (Paris, France) derived a score indicating treatment eligibility by a stepwise logistic regression using a cohort of 804 chronic HBV infections in The Gambia. They subsequently validated the score in an external cohort of 327 HBV-infected Africans from Senegal, Burkina Faso, and Europe. The team has developed and validated a diagnostic score, known as TREAT-B (treatment eligibility in Africa for the HBV), which is based on simple blood tests that are widely available in local laboratories in LMICs, and which do not rely on HBV DNA, liver tests or Fibroscan.

HBsAg-positive participants underwent a standardized clinical staging, including fasting transient elastography, abdominal ultrasonography, hematology, biochemistry, hepatitis B e antigen (HBeAg), and HBV DNA using an in-house real-time polymerase chain reaction (PCR, limit of detection: 50 IU/mL).

The team reported that out of several parameters, two remained in the final model, namely HBV e antigen (HBeAg) and ALT level, constituting a simple score (treatment eligibility in Africa for the hepatitis B virus: TREAT-B). The score demonstrated a high area under the receiver operating characteristic curve (0.85, 95% CI 0.79–0.91) in the validation set. The score of 2 and above (HBeAg-positive and ALT ≥20 U/L or HBeAg-negative and ALT ≥40 U/L) had a sensitivity and specificity for treatment eligibility of 85% and 77%, respectively. The sensitivity and specificity of the World Health Organization criteria based on the aspartate aminotransferase-to-platelet ratio index (APRI) and ALT were 90% and 40%, respectively.

The authors concluded that TREAT-B represents a promising simple and low-cost diagnostic score that can assist physicians to easily identify HBV-infected individuals in need of treatment in Africa. Its use may contribute towards global HBV elimination by facilitating the scale up and decentralization of HBV treatment programs in LMICs. Both ALT and HBeAg measurements are widely available in LMICs, and their total cost of less than USD 10 is much lower than the cost of the conventional tests required indicating treatment eligibility. The study was published on July 1, 2018, in the Journal of Hepatology.

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