Evaluation of Serum Cotinine Cut-Off to Distinguish Smokers From Nonsmokers in the Korean Population

BACKGROUND: Cotinine has been widely used as an objective marker to identify current smokers. We conducted this study to address the absence of Korean studies investigating the efficacy of immunoassays and liquid chromatography-tandem mass spectrometry (LC-MS/MS) for the detection of serum cotinine and to determine the optimal serum cotinine cut-off level for differentiating current smokers from nonsmokers. METHODS: Serum specimens were obtained from 120 subjects. They were randomly chosen to represent a broad distribution of urine cotinine levels based on a retrospective review of questionnaires and results of urine cotinine levels. We determined serum cotinine levels using the IMMULITE 2000 XPi Immunoassay System (Siemens Healthcare Diagnostics Inc., USA) and LC-MS/MS (API-4000, Applied Biosystems, USA). Correlation was analyzed between IMMULITE serum cotinine, urine cotinine, and LC-MS/MS serum cotinine levels. ROC curve was analyzed to identify the optimal IMMULITE serum cotinine cut-off level for differentiating current smokers from nonsmokers. RESULTS: IMMULITE serum cotinine levels correlated with both urine cotinine and LC-MS/MS serum cotinine levels, with correlation coefficients of 0.958 and 0.986, respectively. The optimal serum cotinine cut-off level for distinguishing current smokers from nonsmokers was 13.2 ng/mL (95.7% sensitivity, 94.1% specificity) using IMMULITE. CONCLUSIONS: This is the first study to investigate the use of LC-MS/MS for the measurement of serum cotinine and to determine the optimal serum cotinine cut-off level for the IMMULITE immunoassay. Our results could provide guidelines for differentiating current smokers from nonsmokers in the Korean population.

Identification of Mixed Lineage Leukemia Gene (MLL)/MLLT10 Fusion Transcripts by Reverse Transcription-PCR and Sequencing in a Case of AML With a FISH-Negative Cryptic MLL Rearrangement

No abstract available.

Evaluation of Analytical Performance of the Cobas 8000 Analyzer Series Module e602

BACKGROUND: The e602, a module of the recently released cobas 8000 modular analyzer series, is an automated system for immunoassays. In this study, we evaluated its analytical performance using 17 immunoassay analytes. METHODS: The Clinical Laboratory Standards Institute guidelines were used to determine the efficiency of the cobas 8000 e602 based on its precision, linearity, assay comparison, and reference range validation. Performance analyses were completed using two levels of quality control materials and pooled sera from our institution. The performance of the cobas 8000 e602 was compared to that of the modular analytics E170. Statistical analyses were performed using Excel 2010 (Microsoft Co., USA) and EP Evaluator Release 10 (Data Innovations, USA). RESULTS: For all analytes, except level 1 total vitamin D, the coefficients of variation were 0.975 for all analytes. The reference range validation was also within the allowable criteria. CONCLUSIONS: Taken together, these findings demonstrate that the cobas 8000 e602 analyzer has good precision, linearity, performance comparison, and reference range validation. Thus, e602 is a useful module of the cobas 8000 modular analyzer series.

Acute Megakaryoblastic Leukemia with CD41a-/CD61-/CD42a+ Blasts in an Infant with Down Syndrome

Infants with Down syndrome have increased incidences of transient abnormal myelopoiesis (TAM) and acute leukemia, which are usually associated with acute megakaryoblastic leukemia (AMKL). A 5-day-old girl with Down syndrome was diagnosed with TAM; 4 months later, acute leukemic transformation was suspected. Bone marrow (BM) examination was performed, and the infant was diagnosed with acute leukemia (80% blasts). Although BM aspirates showed the presence of megakaryocytic blasts with cytoplasmic blebs, flow cytometry analysis revealed that they were negative for cells with CD41a and CD61 immunophenotypes. Further analysis revealed that the megakaryocyte-related marker CD42a was positive in 57% of blasts. Morphologic and immunophenotypic features are required to establish the lineage of megakaryocytic blasts, which are necessary for diagnosing AMKL. As most cases of AMKL were positive for CD41 and/or CD61 markers, their presence was evaluated during routine analysis. In order to identify the immunophenotypic features of AMKL in an infant with Down syndrome, we performed additional flow cytometry for CD42a, one of the megakaryocytic markers, and were able to assist in the early diagnosis of AMKL, as well as to use CD42a as an effective follow-up marker.