Influenza A (H1N1) 2009 monovalent and seasonal influenza vaccination among adults 25 to 64 years of age with high-risk conditions--United States, 2010.

BACKGROUND: Seasonal influenza vaccination has been routinely recommended for adults with high-risk conditions. The Advisory Committee on Immunization Practices recommended that persons 25 to 64 years of age with high-risk conditions be one of the initial target groups to receive H1N1 vaccination during the 2009-2010 season. METHODS: We used data from the 2009-2010 Behavioral Risk Factor Surveillance System survey. Vaccination levels of H1N1 and seasonal influenza vaccination among respondents 25 to 64 years with high-risk conditions were assessed. Multivariable logistic regression models were performed to identify factors independently associated with vaccination. RESULTS: Overall, 24.8% of adults 25 to 64 years of age were identified to have high-risk conditions. Among adults 25 to 64 years of age with high-risk conditions, H1N1 and seasonal vaccination coverage were 26.3% and 47.6%, respectively. Characteristics independently associated with an increased likelihood of H1N1 vaccination were as follows: higher age; Hispanic race/ethnicity; medical insurance; ability to see a doctor if needed; having a primary doctor; a routine checkup in the previous year; not being a current smoker; and having high-risk conditions other than asthma, diabetes, and heart disease. Characteristics independently associated with seasonal influenza vaccination were similar compared with factors associated with H1N1 vaccination. CONCLUSION: Immunization programs should work with provider organizations to review efforts made to reach adults with high-risk conditions during the recent pandemic and assess how and where they can increase vaccination coverage during future pandemics.

Interlaboratory comparison study of serum total testosterone [corrected] measurements performed by mass spectrometry methods.

BACKGROUND: Though mass spectrometry (MS) assays are increasingly used for routine clinical measurements of serum total testosterone (TT), information about the variability of results is limited. This study assessed the variability of TT measurement results from routine MS assays. METHODS: Twenty serum samples (12 females, 8 males) were analyzed on 2 days by seven high performance liquid chromatography (HPLC), and one gas chromatography (GC)-tandem mass spectrometry (HPLC-MS/MS, GC-MS/MS) assays. Two samples (male and female) were provided in five replicates to assess the within-run variability. Results were compared against those obtained at National Institute of Standards and Technology (NIST). The within- and between-laboratory variability was assessed for each sample. Comparisons to the NIST results were performed using bias plot and Deming regression analysis. RESULTS: The overall coefficient of variation of the results obtained with MS assays was <15%CV at >1.53 nmol/L and <34%CV at 0.3 nmol/L. The between-assay variability was the major contributor to the overall variability. The assay precision was the highest (<3%CV) with assays using liquid-liquid extraction for sample preparation or GC-MS/MS. The mean percent difference to the reference assay was 11%. The slopes of Deming regression analysis of the MS assays were between 0.903 and 1.138 (correlation coefficient: >0.996). TT concentrations for one assay were above the measurement range. CONCLUSIONS: The variability of TT measurement results among MS assays is substantially smaller than that reported for immunoassays. The type of sample preparation may affect assay precision. Standardizing assays can further reduce the variability of measurement results.

Standardization of high-sensitivity immunoassays for measurement of C-reactive protein; II: Two approaches for assessing commutability of a reference material.

BACKGROUND: We evaluated the commutability of a proposed reference material (PRM), with a formulation based on dilution of Certified Reference Material 470 (CRM470), for 24 high-sensitivity C-reactive protein (hsCRP) methods. We also investigated whether calibration by use of PRM was effective in harmonizing results. METHODS: A set of 40 native clinical samples was measured along with PRM and 3 dilutions of PRM. We used weighted least-squares polynomial regression (WLS/PR) to perform comparisons between all method combinations and to calculate normalized residuals for the PRM. The PRM was considered noncommutable if any of the normalized residuals for a method pair was >2. Correspondence analysis (CA) was used to explore the multidimensional relationships between methods and samples to evaluate if the PRM had properties similar to native clinical samples. Clinical sample results from the methods for which PRM was commutable were recalibrated based on the PRM results, and ANOVA was used to estimate the CVs before and after recalibration. RESULTS: After omitting data for 9 methods because of poor precision or procedural flaws, we used data from the 15 remaining methods to evaluate commutability. Using both WLS/PR and CA we found that PRM was noncommutable with 1 method. We found modest improvement in total and among-method CVs when PRM was used to harmonize the results from the 14 methods for which it was commutable. CONCLUSIONS: A PRM with a formulation based on dilution of CRM470 was commutable with native clinical samples for 14 of 15 hsCRP methods that had acceptable precision. For those methods the use of PRM may contribute to improved harmonization of results for native clinical samples.