[Performance evaluation of Real-Q Enterovirus Quantification kit for enterovirus by real-time PCR].

BACKGROUND: Molecular methods have enabled rapid diagnosis of aseptic meningitis and have reduced both unnecessary therapeutic interventions and medical costs. In this study, we evaluated the analytical performance of the recently developed Real-Q Enterovirus Quantification kit (BioSewoom Inc., Korea). METHODS: We evaluated the detection limit, precision, linearity, and cross-reactivity of the Real-Q Enterovirus Quantification kit and compared it with the conventional PCR method. From March to September 2009, we tested 91 CSF specimens from patients who visited the pediatrics department of the university hospital with symptoms of aseptic meningitis or infantile sepsis, and we also tested 48 CSF specimens from patients with febrile convulsion for differential diagnosis. RESULTS: The Real-Q Enterovirus Quantification kit showed good linearity (r=0.997) within a range from 3 × 10(2) to 3 × 10(10) copies/mL, and the detection limit of the kit was 83 copies/mL. The within-run, between-run, and between-day CVs were 5.3-7.6%, 9.5-12.3%, and 11.4-13.4%, respectively. There was no cross reactivity between enteroviruses and various microorganisms. Positive results were obtained for 39.1% (25/64) of the patients suspected of aseptic meningitis and 44.4% (12/27) of the patients suspected of infantile sepsis. However, among the 48 children with febrile conversion, only 4 were positive for enterovirus. Further, the concordance with conventional PCR was high (73/74). CONCLUSIONS: The Real-Q Enterovirus Quantification kit showed excellent linearity and high reliability with a broad reportable range. It showed good detection rate when used with clinical specimens and also showed a high concordance with the conventional method. Therefore, this assay would be clinically useful not only in diagnosis of aseptic meningitis but also in differential diagnosis of infantile sepsis.

[Evaluation of ARCHITECT HCV core antigen assay].

BACKGROUND: Hepatitis C virus (HCV) core antigen (Ag) levels are known to be well correlating with HCV RNA levels, and may be used as an alternative marker of HCV replication for monitoring the response to HCV treatment. However, the low sensitivity of HCV core Ag assay has been an obstacle for clinical use. In this study, recently developed ARCHITECT HCV Ag assay (Abbott Laboratories, USA) was evaluated for analytical performance and clinical usefulness. METHODS: A total of 109 sera from HCV infected patients including various genotypes of HCV (1b, 2, 2a/2c, 2b, and 3a) and 20 sera from healthy donors were used for evaluating the sensitivity, precision, and linearity of the HCV core Ag assay. The cross reactivity with HIV, hepatitis B virus and myeloma proteins (N=5, each) and correlation with HCV RNA PCR assay were also evaluated. RESULTS: The sensitivity of the HCV core Ag assay was 97.2% (106/109) and there were no false positive results and cross reactivity. The within-run, between-run and between-day CVs were 3.0%, 2.5% and 3.0%, respectively. The levels of HCV core antigen showed a good correlation with those of HCV RNA quantification (r=0.940). The HCV Ag assay showed an excellent linearity in the range from 0.63 to 17,114 fmol/L (r=0.999). CONCLUSIONS: The ARCHITECT HCV Ag assay was good in sensitivity, precision, and linearity and its results well correlated with HCV RNA levels. This assay could be used as a good marker of viral replication for monitoring the therapy response in chronically HCV infected patients.