BACKGROUND: Mycoplasma pneumoniae is the most frequent cause of respiratory tract infections in school-aged children and adolescents. M. pneumoniae infection has variable clinical manifestations and is resistant to beta-lactam antibiotics, making correct diagnosis important. We evaluated the newly introduced Chorus M. pneumoniae IgM (DIESSE Diagnostica, Italy) assay for early diagnosis of M. pneumoniae infection. METHODS: The Chorus M. pneumoniae IgM and particle agglutination (PA) (Fujirebio, Japan) assays were tested on 75 serum specimens from 52 hospitalized children at a tertiary-care hospital between September 2011 and November 2011. A positive PA result was defined as an antibody titer of > or =1:40. The concordance of the Chorus M. pneumoniae IgM and PA results and the correlation of the Chorus M. pneumoniae IgM Index with the PA titer were analyzed. Furthermore, the Chorus M. pneumoniae IgM and PA results (PA-patient positive/negative) based on the clinical cutoff of the PA assay were compared in acute-phase specimens. RESULTS: The concordance rate of the Chorus M. pneumoniae IgM and PA results was 90.7% (kappa value= 0.5), and the Chorus M. pneumoniae IgM Index and PA titer correlated well (Spearman's correlation coefficient, 0.872, P < 0.001). However, 82.6% (19/23) of patients who were negative for M. pneumoniae by PA using the clinical cut-off were Chorus M. pneumoniae IgM-positive. CONCLUSIONS: The Chorus M. pneumoniae IgM assay is convenient and gives objective results. However, to make Chorus suitable for routine laboratory use, additional validation studies are required to determine the criteria for use in convalescent specimens.
Adolescent ; Agglutination ; Anti-Bacterial Agents ; Child ; Child, Hospitalized ; Early Diagnosis ; Humans ; Immunoenzyme Techniques ; Immunoglobulin M ; Mycoplasma ; Mycoplasma pneumoniae ; Pneumonia ; Pneumonia, Mycoplasma ; Respiratory Tract Infections

BACKGROUND: We evaluated the diagnostic performance of a newly developed Elecsys Anti-HCV II assay in Korean patients. METHODS: A total of 500 serum samples (400 antibody to hepatitis C virus [anti-HCV]-negative and 100 anti-HCV-positive samples) were collected after testing with Elecsys Anti-HCV assay (Roche Diagnostics, Germany). All the samples were tested for anti-HCV by using Vitros Anti-HCV (Ortho-Clinical Diagnostics, UK) and Elecsys Anti-HCV II (Elecsys II) (Roche Diagnostics, Germany) assays. Specimens that were found to be positive or negative in all the 3 assays were considered positive or negative for anti-HCV, respectively, and medical records of the patients, including results of previous HCV tests, were reviewed to determine the final results for anti-HCV when there were discrepancies among the results of the anti-HCV assays. RESULTS: Discrepancies between the results of the 3 anti-HCV assays were found for 4 of the 500 samples (0.8%). Sensitivity/specificity values for Elecsys II were 98.0%/100.0%, and the corresponding values for Elecsys and Vitros assays were 100.0%/100.0% and 100.0%/99.5%. Concordance rates between the results of any 2 of the 3 assays were equal or greater than 99.2%, with a kappa coefficient of 0.98 or greater (P < 0.0001). CONCLUSIONS: Sensitivities and specificities of the anti-HCV assays evaluated in this study were high enough for being used in clinical laboratories, and the results of the 3 assays showed good agreement. However, samples for which weak-positive results were obtained would need to be retested, considering the discrepancies between the anti-HCV assays.
Hepacivirus ; Hepatitis C Antibodies ; Humans ; Medical Records

BACKGROUND: In 2010, the Clinical and Laboratory Standards Institute (CLSI) revised the minimum inhibitory concentration (MIC) breakpoints of cephalosporins and aztreonam to exempt extended-spectrum beta-lactamase (ESBL) confirmatory tests for Enterobacteriaceae. However, the CLSI did not change the MIC breakpoint of cefepime. Here, a proficiency survey of a strain of ESBL-producing Klebsiella pneumoniae was analyzed for MIC distribution and interpretation of cephalosporins and aztreonam. METHODS: The survey strain, K. pneumoniae, which produced SHV-18, was distributed to 170 clinical laboratories as 1 of 5 presumptive clinical specimens through the proficiency survey of the clinical microbiology division of the Korean Association of Quality Assurance for Clinical Laboratories (KAQACL). MIC, zone diameter of inhibition (ZDI), and interpretation of tested antimicrobials, methods of antimicrobial susceptibility testing (AST), and ESBL confirmatory results were collected. RESULTS: According to the revised breakpoints of the 2010 CLSI guidelines, MIC results indicated resistance to aztreonam in 100%, cefepime in 5.5%, cefotaxime in 20%, ceftazidime in 100%, and ceftriaxone in 100% of samples by broth microdilution methods. ZDI results also indicated resistance to aztreonam in 75%, cefepime in 0%, cefotaxime in 66.7%, ceftazidime in 100%, and ceftriaxone in 80% of samples by disk diffusion method. Ninety (75.6%) participants performed an ESBL confirmatory test, and 89 (98.9%) reported ESBL-positive tests. Of the 55 laboratories that tested the susceptibility of cefepime, 50 (90.9%) self-reported to be "resistant" because of ESBL-positive results. CONCLUSIONS: In conclusion, susceptibility testing of ESBL producers against certain cephalosporins is not reliable enough to apply the revised breakpoints presented in the 2010 CLSI guidelines. It is therefore necessary to reach a consensus for interpretation of ASTs of ESBL producers in Korea. Ideally, clinicians should be provided two interpretations based on both the revised breakpoints and ESBL confirmatory testing.
Aztreonam ; beta-Lactamases ; Cefotaxime ; Ceftazidime ; Ceftriaxone ; Cephalosporins ; Consensus ; Diffusion ; Enterobacteriaceae ; Klebsiella ; Klebsiella pneumoniae ; Korea ; Microbial Sensitivity Tests ; Pneumonia ; Sprains and Strains

BACKGROUND: Community-acquired pneumonia (CAP) is a leading cause of infectious diseases and mortality. CAP is primarily treated by administration of adequate antibiotics against the causative pathogens. Because detection of some pathogens by the conventional culture method is difficult, the use of molecular diagnostic methods is increasing. Although an optimal specimen type is very important for proper testing, there is no consensus on the optimal specimen type for detecting CAP pathogens. In this study, we compared sputum specimens and nasopharyngeal aspirates (NPAs) for molecular detection of 4 CAP-causing bacterial species. METHODS: From September 2011 to January 2012, we collected sputum specimens and NPAs from CAP patients on the first or second day of hospitalization. The specimens were tested for Mycoplasma pneumoniae, Streptococcus pneumoniae, Chlamydophila pneumoniae and Legionella pneumophila by using commercial real-time PCR. RESULTS: We collected 63 sputum specimens and 96 NPAs from 109 patients and found positive results for 38.1% (24/63) and 28.1% (27/96), respectively (P = 0.251). There were no significant differences in the positive rates obtained for sputum specimens of different quality. CONCLUSIONS: The results obtained using NPAs and sputum specimens for the molecular detection of CAP pathogens were comparable.
Anti-Bacterial Agents ; Chlamydial Pneumonia ; Chlamydophila pneumoniae ; Communicable Diseases ; Consensus ; Hospitalization ; Humans ; Legionella pneumophila ; Mycoplasma pneumoniae ; Pathology, Molecular ; Pneumonia ; Pneumonia, Mycoplasma ; Real-Time Polymerase Chain Reaction ; Sputum ; Streptococcus pneumoniae

BACKGROUND: Neutrophil gelatinase-associated lipocalin (NGAL) has recently been introduced as a renal biomarker and an increase in its level suggests tubular injury. Diabetic nephropathy, a leading cause of end-stage renal disease, causes typical changes characterized by glomerulosclerosis and eventual tubular damage in the kidney. In the present study, we attempted to validate the usefulness of plasma NGAL (pNGAL) as a biomarker for tubular damage in diabetic nephropathy. METHODS: The plasma NGAL levels of 260 diabetes mellitus patients and 50 healthy individuals werewas measured by means of fluorescent immunoassay using with the Triage NGAL test (Biosite, USA). The patients were divided into 3 groups on the basis of their urinary albumin excretion (UAE) levels, and the pNGAL differences among each group were analyzed. The degree of albuminuria and cystatin C-based glomerular filtration rate (GFR) were also compared with the pNGAL levels. RESULTS: The mean pNGAL levels of the normal subjects and diabetic patients were 61.9 +/- 4.81 ng/mL and 93.4 +/- 71.78 ng/mL, respectively. pNGAL level was significantly increased in patients with severe albuminuria (P < 0.001). The pNGAL level was found to be positively correlated with the degree of albuminuria (R2 = 0.218, P < 0.001) and inversely correlated with GFR (R2 = 0.269, P < 0.001). Particularly, the pNGAL level of patients with diabetic nephropathy was found to be associated with the renal damage and independent of other factors influencing the renal damage (R2 = 0.218). CONCLUSIONS: pNGAL level independently reflects renal damage in patients with diabetic nephropathy. Measurement of pNGAL level combined with UAE would help enable to detect both glomerular and tubular damage in diabetic nephropathy patients.
Albuminuria ; Diabetes Mellitus ; Diabetic Nephropathies ; Glomerular Filtration Rate ; Humans ; Immunoassay ; Kidney ; Kidney Failure, Chronic ; Lipocalins ; Neutrophils ; Plasma ; Triage

BACKGROUND: Hemoglobin A1c (HbA1c) levels are widely used to monitor glycemic control in diabetes mellitus patients, and various methods are used for determining HbA1c levels. The ADAMS A1c HA-8180 (Arkray, Inc., Japan) is a fully automated HbA1c analyzer based on high-performance liquid chromatography (HPLC). METHODS: The analytical performance of the ADAMS A1c HA-8180 analyzer was evaluated on the basis of its precision, linearity, correlation with the Variant II Turbo (Bio-Rad Laboratories, USA), and agreement with the National Glycohemoglobin Standardization Program (NGSP) targets. All evaluations were performed according to Clinical and Laboratory Standard Institute (CLSI) guidelines EP05, EP06, and EP09. RESULTS: Coefficients of variation (CVs) for total precision at low and high levels were 0.99% and 1.16%, respectively. The linearity was excellent with R2 = 0.99 in the range of 4.98-15.10%. Its analytical performance was well correlated with that of Variant II Turbo (r = 0.9987). The 95% confidence interval of bias between the NGSP target and the levels measured using the ADAMS A1c HA-8180 was -0.402-0.225. CONCLUSIONS: The ADAMS A1c HA-8180 showed excellent precision, linearity, correlation with Variant II Turbo, and agreement with the NGSP target. Therefore, its analytical performance is satisfactory for diagnosis and treatment monitoring of diabetes.
Bias (Epidemiology) ; Chromatography, Liquid ; Diabetes Mellitus ; Hemoglobins ; Humans ; Organothiophosphorus Compounds

BACKGROUND: Hemoglobin A1c (HbA1c) is a useful marker for the diagnosis and monitoring of diabetes, which has resulted in an increasing dependency on HbA1c levels for diagnosing diabetes in small- and medium-sized hospitals. We evaluated a high performance liquid chromatography (HPLC) based HbA1c autoanalyzer Bio-Rad D-10 (Bio-Rad Laboratories, USA) by comparing the analysis results with that by Tosoh HLC-723 G7 (Tosoh Corporation, Japan). METHODS: The Bio-Rad D-10 autoanalyzer was evaluated for its precision, linearity, and carryover. The analysis time and correlation were evaluated and compared with those by Tosoh HLC-723 G7 autoanalyzer. RESULTS: Bio-Rad D-10 showed within-run, between-day, and total precision of less than 1.3% coefficient of variation (CV) and excellent linearity between HbA1c in the range of 3.2%-21% (coefficient of determination, R 2 = 0.998). The sampleto-sample carryover was 0.57%. The results obtained by using Bio-Rad D-10 showed good correlation (r = 0.997; P < 0.001) with those by Tosoh HLC-723 G7; however, the analysis time using Bio-Rad D-10 was about 2.3 times per 10 samples and 2.5 times per 20 samples than those using Tosoh HLC-723 G7. CONCLUSIONS: Bio-Rad D-10 showed good performance in assaying HbA1c. Bio-Rad D-10 autoanalyzer would be suitable for use in laboratories with small to medium amount of samples to be analyzed, but its initial analyzing time was longer than that by Tosoh HLC-723 G7.
Chromatography, Liquid ; Dependency (Psychology) ; Hemoglobins

BACKGROUND: Laboratory diagnosis for ovarian cancer is mostly based on the quantitative determination of CA125. Over the past years, a number of additional markers for ovarian cancer have been proposed and studied. Human epididymis protein 4 (HE4) has accordingly emerged as a new biomarker for the detection of ovarian cancer. To evaluate the new automated HE4 assay, we studied analytical performance, and established reference ranges. METHODS: We evaluated precision performances and linearity of the HE4 assay. We also evaluated reference ranges for HE4 and CA125 according to age. Lastly, we investigated the correlation between HE4 and CA125. RESULTS: The precision study showed excellent results for both high and low control. The 95% upper reference ranges for HE4 and CA125 levels were 81.0 pmol/L (90% confidence interval [CI], 63.0-103.1) and 28.6 U/mL (90% CI, 25.4-36.4), respectively. There was no correlation between HE4 and CA125 (r = -0.002, P = 0.9793) in healthy women. Reference ranges of HE4 tended to be slightly higher for the older groups as compared to the younger groups. CA125 were considerably decreased in the oldest age group (ages 70 to 79). CONCLUSIONS: The new automated HE4 assay showed good analytical performance, age-related variable results and no correlation with CA125. Though further studies for clinical and diagnostic effectiveness of HE4 assay in screening and diagnosing ovarian cancer are needed for routine use of HE4, HE4 in combination with CA125 is likely to be more useful diagnostically than CA125 alone.
Clinical Laboratory Techniques ; Epididymis ; Female ; Humans ; Male ; Mass Screening ; Ovarian Neoplasms ; Reference Values

BACKGROUND: Self-monitoring of blood glucose levels is recommended for all diabetic patients who receive insulin treatment, because such monitoring of glucose levels may aid in achieving better control in type II diabetes. Further, the use of point-of-care (POC) blood glucose testing in hospitals has increased substantially. In the present study, we validated the performance of ACCU-CHEK(R) Inform II Blood Glucose Meter and ACCU-CHEK(R) Performa Strip (Roche Diagnostics, Germany). METHODS: We evaluated the precision, accuracy, and maltose interference of the ACCU-CHEK(R) Inform II Blood Glucose Meter and ACCU-CHEK(R) Performa Strip. Further, precision was evaluated using dedicated quality control (QC) and Bio-Rad Whole Blood (WB) QC materials (Meter Trax(TM) Control; Bio-Rad, USA). Forty samples were used to compare the results obtained using the ACCU-CHEK(R) Inform II Blood Glucose Meter and ACCU-CHEK(R) Performa Strip with those obtained using the clinical chemistry analyzer Hitachi 7600 (Hitachi, Japan). Maltose interference was assessed at 2 glucose concentration levels at 3 maltose concentration levels. RESULTS: For each concentration level of control materials, within-run coefficient of variation (CV) and total CV obtained were less than 5%. Good correlation was obtained using the Hitachi 7600 (y = 1.02x - 0.18; r 2 = 0.996; N = 40). Effects of maltose interference were less than 10%. CONCLUSIONS: Thus, the ACCU-CHEK(R) systems show good precision and correlation with the routine clinical chemistry analyzer and allow only minimal effects of maltose interference.
Blood Glucose ; Chemistry, Clinical ; Glucose ; Humans ; Insulin ; Maltose ; Quality Control

BACKGROUND: Proper gating is important in flow cytometric assays of lymphocyte subsets. Forward light scatter (FSC)/side light scatter (SSC) gating requires application of a lymphocyte purity correction when lymphocyte purity is less than 95%. We compared 3 different gating methods to establish an accurate gating method appropriate for a T-lymphocyte subset assay of bronchoalveolar lavage (BAL) fluid. METHODS: Leukocyte numbers and subtypes in 31 BAL fluid samples were assessed manually and by using an automatic hematology analyzer. T-lymphocyte subsets (T cells, T helper/inducer cells [Th], and T suppressor/cytotoxic cells [Tc]) were assessed by flow cytometry. We compared 3 methods of lymphocyte gating: CD45/SSC gating (reference method), FSC/SSC gating, and FSC/SSC gating with application of a lymphocyte purity correction. Lymphocyte purity was determined by CD45/CD14 staining of BAL fluid. RESULTS: We observed a significant correlation between lymphocyte percentage and lymphocyte purity (r = 0.453, P = 0.011). T-cell results obtained using the reference method were not correlated with the results of the other 2 gating methods (r = 0.189 each, P = 0.308 for FSC/SSC gating and P = 0.310 for FSC/SSC gating with purity correction). Mean differences between the reference method and FSC/SSC gating (T cells: 14.4%, P = 0.002; Th cells: 7.7%, P = 0.006; Tc cells: 7.1%, P = 0.001) were greater than those between the reference method and FSC/SSC gating with purity correction (T cells: 12.1%, P = 0.004; Th cells: 1.7%, P = 0.608; Tc cells: 0.2%, P = 0.957). CONCLUSIONS: Lymphocyte purity correction after FSC/SSC gating improved the accuracy of Th- and Tc-cell measurements, but not T-cell measurements. CD45 is essential for lymphocyte gating in T-lymphocyte subset assays of BAL fluid.
Bronchoalveolar Lavage ; Bronchoalveolar Lavage Fluid ; Flow Cytometry ; Hematology ; Leukocyte Count ; Light ; Lymphocyte Subsets ; Lymphocytes ; T-Lymphocyte Subsets ; T-Lymphocytes