Binnicker, M. J.

ABSTRACT In this study, we compared the performance of six real-time PCR assays for the qualitative detection of cytomegalovirus (CMV) in clinical samples other than plasma. Two hundred specimens (respiratory [ n = 72], urine [ n = 67], cerebrospinal fluid [CSF] [ n = 25], tissue [ n = 18], amniotic fluid [ n = 10], and bone marrow [ n = 8]) submitted for routine testing by CMV real-time PCR analyte-specific reagents (ASR) (Roche Diagnostics, Indianapolis, IN) were also tested by a laboratory-developed test (LDT) and 4 commercially available PCR assays: EraGen Multicode (Luminex, Austin, TX), Focus Simplexa (Focus Diagnostics, Cypress, CA), Elitech MGB Alert CMV (Fisher Scientific, Hanover Park, IL), and Abbott CMV (Abbott Park, IL). Nucleic acid was extracted using the MagNA Pure system (Roche Diagnostics) and subsequently tested by each PCR method. Results were analyzed by comparing each assay to a “consensus result,” which was defined as the result obtained from at least 4 of the 6 assays. In addition to the prospective samples, 13 lower respiratory samples with known positive results by CMV shell vial were tested by each PCR method. Following testing of the 200 prospective specimens, the Abbott, Elitech, EraGen, and Focus PCR assays demonstrated a sensitivity of 100% (46/46), while the Roche analyte-specific reagents (ASR) and LDT showed sensitivities of 89% (41/46) and 98% (45/46), respectively. Percent specificities ranged from 97% (149/154) by Elitech to 100% (154/154) by the LDT. Among the 13 shell vial-positive lower respiratory samples, the percent sensitivities ranged from 69% (9/13) by Elitech to 92% (12/13) by the LDT. The Abbott, EraGen, Elitech, Focus, and LDT PCR assays performed similarly (κ ≥ 0.89) for the detection of CMV in clinical specimens and demonstrated increased sensitivity compared to the Roche ASR.

ABSTRACT We compared the performance of four assays for the detection of cryptococcal antigen in serum samples ( n = 634) and cerebrospinal fluid (CSF) samples ( n = 51). Compared to latex agglutination, the sensitivity and specificity of the Premier enzyme immunoassay (EIA), Alpha CrAg EIA, and CrAg lateral flow assay (LFA) were 55.6 and 100%, 100 and 99.7%, and 100 and 99.8%, respectively, from serum samples. There was 100% agreement among the four tests for CSF samples, with 18 samples testing positive by each of the assays.

ABSTRACTConventional methods for the detection of Epstein-Barr virus (EBV)-specific antibodies include the immunofluorescence assay (IFA) and enzyme immunoassay (EIA). While sensitive and specific, these methods are labor-intensive and require separate assays for each analyte. This study evaluated the performance of a multiplex bead assay (BioPlex 2200; Bio-Rad Laboratories, Hercules, CA) for the simultaneous detection of immunoglobulin G (IgG) and IgM class antibodies to the EBV viral capsid antigen (VCA) and IgG class antibodies to Epstein-Barr virus nuclear antigen-1 (EBNA-1). Serum specimens (n= 1,315) submitted for routine EBV-specific antibody testing by EIA (Grifols-Quest, Inc., Miami, FL) were also tested by the multiplex bead assay using the BioPlex 2200 automated analyzer. Specimens showing discordant results were tested by IFA. Following IFA resolution, the BioPlex VCA IgM, VCA IgG, and EBNA-1 IgG assays demonstrated 97.9%, 91.4%, and 96.9% agreement, respectively, with the results obtained by EIA. Furthermore, the BioPlex assays showed an overall agreement of 94.1% with the EIA when the specimens were categorized by disease state (susceptible, acute, or past infection) based on the EBV-specific antibody profiles. These findings indicate that the BioPlex EBV assays demonstrate a performance comparable to that of the conventional EIA, while allowing for a more rapid (2.3 h for 100 samples versus 4.5 h by the EIA) and higher-throughput (∼400 samples per 9 h versus 200 samples by the EIA) analysis of the EBV-specific antibody response.

ABSTRACT The diagnosis of Lyme borreliosis (LB) is commonly made by serologic testing with Western blot (WB) analysis serving as an important supplemental assay. Although specific, the interpretation of WBs for diagnosis of LB (i.e., Lyme WBs) is subjective, with considerable variability in results. In addition, the processing, reading, and interpretation of Lyme WBs are laborious and time-consuming procedures. With the need for rapid processing and more objective interpretation of Lyme WBs, we evaluated the performances of two automated interpretive systems, TrinBlot/BLOTrix (Trinity Biotech, Carlsbad, CA) and BeeBlot/ViraScan (Viramed Biotech AG, Munich, Germany), using 518 serum specimens submitted to our laboratory for Lyme WB analysis. The results of routine testing with visual interpretation were compared to those obtained by BLOTrix analysis of MarBlot immunoglobulin M (IgM) and IgG and by ViraScan analysis of ViraBlot and ViraStripe IgM and IgG assays. BLOTrix analysis demonstrated an agreement of 84.7% for IgM and 87.3% for IgG compared to visual reading and interpretation. ViraScan analysis of the ViraBlot assays demonstrated agreements of 85.7% for IgM and 94.2% for IgG, while ViraScan analysis of the ViraStripe IgM and IgG assays showed agreements of 87.1 and 93.1%, respectively. Testing by the automated systems yielded an average time savings of 64 min/run compared to processing, reading, and interpretation by our current procedure. Our findings demonstrated that automated processing and interpretive systems yield results comparable to those of visual interpretation, while reducing the subjectivity and time required for Lyme WB analysis.