Comparative evaluation of ADVIA Centaur® XP chemiluminescence system for screening of HBV, HCV, HIV and syphilis in Indian blood donors.

BACKGROUND: The introduction of chemiluminescent immunoassay (CLIA) in blood donor screening has led to a gradual replacement of enzyme-linked-immunosorbent assay (ELISA) as the former offers automation, higher sensitivity and lower turn-around-time. However, only a few CLIA platforms are used for blood donor screening in India. The present study evaluated one such newer platform viz., Adiva Centaur XP CLIA for screening of HBV, HCV, HIV and syphilis. MATERIAL AND METHODS: Prospective comparative study wherein 4843 whole blood donors were screened for HBsAg, Anti-HCV, HIV Ag-Ab and Anti-treponemal antibodies in both Advia Centaur XP and Architect i2000SR platforms. Additional tests were performed in samples which were reactive in only one of the platforms. The sensitivity, specificity, positive predictive value, negative predictive value, accuracy, false positive rate and false negative rate of both the platforms were compared. Kappa coefficient was calculated to determine the agreement between the testing platforms. RESULTS: The sensitivity of Advia Centaur platform for HBV, HCV, HIV and syphilis detection were 94.9 %, 100 %, 100 % and 100 % respectively as compared to 96.6 %, 100 %, 100 % and 100 % in Architect i2000SR platform. The specificity of both the platforms were 99.8-99.9 % for all the four tests. The agreement between the two platforms was almost perfect for HBV, HCV and syphilis testing; and fair for HIV testing. CONCLUSION: The Advia Centaur CLIA platform was found to be comparable with the Architect CLIA platform for blood donor screening. Unexpected finding was the occurrence of HBV false negatives in both the platforms, possibly due to HBsAg mutations.

Assessment of dengue virus inactivation in random donor platelets using amotosalen and ultraviolet A illumination.

OBJECTIVES: The study objective was evaluation of amotosalen and ultraviolet A (UVA) illumination-based inactivation of dengue virus (DENV) in blood platelets. MATERIALS AND METHODS: Whole blood was collected from healthy donors and platelet concentrates were prepared at a tertiary care hospital in Gurugram, India. Platelet units collected from five blood group matched individuals were pooled and spiked with DENV. The spiked platelet units were subjected to amotosalen treatment followed by UVA illumination, to evaluate the efficiency of this method for viral inactivation. The treated platelet units were evaluated for the presence of infectious DENV. Amotosalen levels were quantified in the treated samples using high-performance liquid chromatography. RESULTS: The presence of replicating DENV was not observed in spiked platelet units treated with amotosalen and UVA illumination, whereas untreated units contained actively replicating DENV. Amotosalen levels were found to be in the permissible range after photochemical inactivation. CONCLUSIONS: Amotosalen/UVA pathogen inactivation treatment showed efficient inactivation of DENV in platelet components. Therefore, it seems to be a promising method for mitigating the risk of dengue transmission through transfusion of potentially contaminated platelet components in dengue-endemic countries such as India.

Sensitivity of individual and mini-pool nucleic acid testing assessed by dilution of hepatitis B nucleic acid testing yield samples.

INTRODUCTION: For nucleic acid testing (NAT) of blood donations, either the blood samples can be pooled together in a batch of six or eight prior to testing (mini-pool-NAT [MP-NAT]), or the tests can be run on every individual sample (individual donor-NAT [ID-NAT]). It has been debated in various studies whether pooling of samples results in decreased sensitivity of detection as the volume of individual samples gets lesser in a pool. The objective of this study was to investigate the effect of dilution on the sensitivity of tests. MATERIALS AND METHODS: The study was performesd on nine plasma samples which were hepatitis B reactive exclusively by Procleix Ultrio Plus and not by Procleix Ultrio or serology. These nine exclusive UltrioPlus ID-NAT yield samples were diluted in 1:2, 1:4. 1:6 and 1:8 dilutions using previously tested negative plasma and each dilution of every sample along with archived undiluted sample were retested in three replicates with Procleix Ultrio Plus Assay. RESULTS: Among NAT yield samples, 88.88% of the samples were detected when retested in ID-NAT in undiluted form. Samples with higher viral load (sample 5 and 6) were detected by all dilutions. When samples with viral load below 20 IU/mL were tested in dilutions of 1:6 or 1:8, only 9 out of 27 replicates (33.33%) were detected. This means that more than 67% of low viral load samples were missed by MP-NAT of 1:6 or 1:8 dilution out of total NAT yield samples. CONCLUSION: Individual Donor NAT is ideal methodology for NAT as dilution due to pooling may miss samples with low viral load as evident in this study.