The electrochemiluminescence immunoassay (ECLIA) can detect hepatitis B and C markers in dried blood spots (DBSs), according to results published in BMC Research Notes. DBSs are an alternative to serum samples that can be easily collected and transported to reference laboratories without refrigeration.

The study included paired plasma and DBS samples collected at the Viral Hepatitis Clinic in Rio de Janeiro, Brazil (n=1385). The researchers used the Kappa index to obtain concordance between the results for paired DBS and serum samples. They performed analyses using GraphPad InStat 3.01 (GraphPad Software).

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Of all the paired samples, 71 were HBsAg positive, 185 were anti-HBc positive, 108 were anti-HCV positive, 298 were HBsAg negative, 357 were anti-HBc negative, and 366 were anti-HCV negative.

In 108 paired, anti-HCV positive serum samples, the researchers detected anti-HCV in 103 DBS samples. In 366 paired, anti-HCV negative serum samples, anti-HCV was undetected in 364 samples. Taken together, this represents a sensitivity of 95.4% and a specificity of 99.4%.

HBsAg was detected in 67 DBS samples out of 71 positive paired serum samples, and it was undetected in 295 DBS samples out of 298 negative paired serum samples for a sensitivity of 94.4% and specificity of 99%.

Of 185 paired anti-HBc positive serum samples, anti-HBc was detected in 160 DBS samples. Out of 357 paired anti-HBc negative serum samples, anti-HBc was undetected in 349 DBS samples for a sensitivity of 86.5% and a specificity of 97.8%.

The researchers found that the Kappa index showed a high agreement between results obtained for the serum samples compared with the DBS samples (Kappa index: .95 for anti-HCV, .93 for HBsAg, and .86 for anti-HBc).

“DBS specimens could be a reliable alternative testing specimen, which may increase hepatitis B and C diagnostic opportunities for rural, remote, and hard to reach regions,” the researchers wrote.

Reference

Villar LM, Cruz HM, Deodato RM, et al. Usefulness of automated assays for detecting hepatitis B and C markers in dried blood spot samples. BMC Res Notes. 2019;12(1):523.