Comparison between DiaPlexQ™ STI6 and GeneFinder™ STD I/STD II multiplex Real-time PCR Kits in the detection of six sexually transmitted disease pathogens.

BACKGROUND: The DiaPlexQ™ STI6 Detection Kit (DiaPlexQ; Solgent Co., Ltd., Daejeon, South Korea) is a multiplex real-time PCR assay for the detection of the following sexually transmitted disease (STD) pathogens: Chlamydia trachomatis, Neisseria gonorrhoeae, Mycoplasma hominis, Trichomonas vaginalis, Ureaplasma urealyticum, and Mycoplasma genitalium. We compared the performance of the DiaPlexQ assay with the GeneFinder™ STD I (CT/NG/UU) and STD II (MG/MH/TV) Multiplex Real-time PCR Kits (GeneFinder; Infopia Co., Ltd., Anyang, South Korea). METHODS: We evaluated the performance of the DiaPlexQ assay in comparison to that of GeneFinder using 1106 clinical specimens (542 genital swabs and 564 urine samples). The analytical performance of the DiaPlexQ assay, including the limit of detection (LOD) and analytical specificity, was evaluated using reference strains. RESULTS: The positive percent agreement, negative percent agreement, and kappa value between the two assays were 96.6%-99.4%, 98.2%-99.8%, and 0.93%-0.99%, respectively. No cross-reactivity was observed in a collection of 41 different microorganisms and the LOD of the DiaPlexQ assay ranged from 1 to 10 copies/reaction for each microorganism. CONCLUSION: The DiaPlexQ assay showed comparable performance to that of the GeneFinder assay so that it can be used for the screening and diagnosis of non-viral curable STD pathogens.

Evaluation of the Bio-Rad Geenius HIV 1/2 Confirmation Assay as an Alternative to Western Blot in the Korean Population: A Multi-Center Study.

Recently updated recommendations for diagnosis of HIV infection suggest a new diagnostic algorithm including HIV-1/HIV-2 antibody differentiation immunoassay instead of western blot (WB) as a confirmatory testing. We evaluated Bio-Rad Geenius HIV1/2 confirmation assay as a simple and reliable alternative to WB in the Korean population with low HIV prevalence. The Geenius HIV1/2 was performed in a total of 192 serum specimens (140 reactive and 52 nonreactive specimens by ARCHITECT HIV Ag/Ab Combo assay) that were prospectively collected from five institutions. HIV-1 nucleic acid amplification test (NAT) was performed in negative or indeterminate specimens by Geenius HIV1/2 or WB. Among 140 reactive specimens by HIV Ag/Ab assay, 82 (58.6%) were positive for HIV-1 Ab by Geenius HIV1/2. Among 58 negative or indeterminate specimens by Geenius HIV1/2, four specimens (6.9%) were positive by HIV-1 NAT. The sensitivity and specificity of Geenius HIV1/2 were 95.3% and 100.0%, respectively. When we considered only WB, the sensitivity and specificity of Geenius HIV1/2 were 100.0% and 99.1%, respectively. Agreement between Geenius HIV1/2 and WB was excellent (weighted Kappa = 0.89). The Geenius HIV1/2 is simple and time-saving compared with WB. It has an excellent performance and can be a reliable alternative to WB. HIV-1 NAT should be performed in negative or indeterminate specimens by Geenius HIV1/2 to detect acute HIV infection as recommended in new HIV testing algorithms.

Comparison of four current 25-hydroxyvitamin D assays.

OBJECTIVES: The performance of recently developed vitamin D total assays (ADVIA Centaur and Elecsys) was compared to that of liquid chromatography-tandem mass spectrometry (LC-MS/MS) and LIASON 25-OH Vitamin D total assays. DESIGN AND METHODS: A total of 157 clinical samples and standard reference material (SRM) 972 were analyzed. RESULTS: The correlations of LC-MS/MS with the three immunoassays were acceptable. However, compared to LC-MS/MS, LIAISON and ADVIA Centaur showed negative bias, and Elecsys showed positive bias. There was a lack of agreement among the four methods with only LC-MS/MS results close to the certified values of SRM 972. The prevalence of vitamin D insufficiency (<50 nmol/L) was higher with ADVIA Centaur (51.6%) and LIAISON (52.2%) and lower with Elecsys (37.6%), compared with that of LC-MS/MS (44.6%). CONCLUSION: The new, automated total vitamin D assays show acceptable correlation with LC-MS/MS, and could be used in routine laboratories. However, standardization of vitamin D assays and consideration of assay-specific decision limits should be addressed.

Malaria detection with the Sysmex XE-2100 hematology analyzer using pseudoeosinophilia and abnormal WBC scattergram.

Recent investigation using the Sysmex XE-2100 hematology analyzer (Sysmex Corporation, Japan) has demonstrated erroneously high eosinophil counts and abnormal white blood cell (WBC) scattergrams in malaria cases. This study was conducted to assess the diagnostic efficiency of the Sysmex XE-2100 analyzer for malaria. One hundred forty-four patients initially diagnosed with Plasmodium vivax infection, 319 patients with febrile illness, and 24 patients who underwent malaria treatment were analyzed. Atypical features on Sysmex XE-2100 analyzer were categorized as pseudoeosinophilia (a gap of more than 5% in eosinophil counts between the Sysmex XE-2100 analyzer and microscopic examination) and abnormal WBC scattergram. Pseudoeosinophilia or abnormal WBC scattergram were detected in 100 of 144 malaria-positive samples (sensitivity 69.4%, specificity 100%). The samples with pseudoeosinophilia or abnormal WBC scattergrams showed significantly higher parasite counts than the samples without pseudoeosinophilia or an abnormal WBC scattergram (P<0.05). All 24 samples from patients for whom the malaria smear was repeated after malaria treatment was initiated showed a normalized eosinophil count and a normal WBC histogram. In conclusion, attention to differential count and WBC scattergrams provided by the Sysmex XE-2100 would be a valuable tool in malaria detection.