Price of High-Throughput 25-Hydroxyvitamin D Immunoassays: Frequency of Inaccurate Results.

BACKGROUND: With a 10-year sustained increase in 25-hydroxyvitamin D [25(OH)D] testing, laboratories have swapped their LC-MS/MS methods for high-throughput automated immunoassays. Although it is generally well-known that immunoassays have poor recoveries for 25-hydroxyvitamin D2 [25(OH)D2], the frequency and extent to which this impacts total 25(OH)D have not been previously demonstrated. We evaluated 3 automated immunoassays against the first FDA-cleared CDC/NIST-traceable LC-MS/MS method. METHODS: Method comparison was performed for the Siemens ADVIA Centaur, Roche Elecsys Cobas, and Abbott Architect 25(OH)D immunoassay methods in real patient samples (n = 105). We calculated the mean bias in samples containing >20 ng/mL 25(OH)D2 and estimated the percent 25(OH)D2 cross-reactivities. We determined the prevalence of appreciable concentrations of 25(OH)D2 in our patient population through random sampling (n = 120) and projected the frequency of inaccurate 25(OH)D immunoassay results. RESULTS: Linear regression for 25(OH)D was y = 1.09x - 4.44 (Centaur), y = 0.84 + 0.43 (Cobas), and y = 0.83x - 0.48 (Architect). The mean biases of 25(OH)D concentrations were 5.6 (11.0) ng/mL (Centaur), -17.5 (7.2) ng/mL (Cobas), and -20.3 (9.8) ng/mL (Architect) in samples containing >20 ng/mL 25(OH)D2. The observed percent cross-reactivities for 25(OH)D2 were 115% (Centaur), 52% (Cobas), and 44% (Architect). We estimate that 8% of our population has >20 ng/mL 25(OH)D2, thereby compromising the accuracy of 25(OH)D results in >3000 samples annually. CONCLUSIONS: We demonstrate that immunoassay manufacturer package inserts indicate much better recoveries of 25(OH)D2 than what is observed in unadulterated real patient samples. We estimate the frequency of inaccurate total 25(OH)D determination by these immunoassay methods to be largely dependent on the concentration of 25(OH)D2 in each sample.

The role of personality traits and barriers to mental health treatment seeking among college students.

Many college students experience a mental health problem yet do not seek treatment from a mental health professional. In the present study, we examined how perceived barriers (stigma perceptions, negative attitudes about treatment, and perceptions of practical barriers), as well as the Big Five personality traits, relate to treatment seeking among college students reporting a current mental health problem. The sample consisted of 261 college students, 115 of which reported experiencing a current problem. Results of a series of logistic regressions revealed that perceived stigma from others (OR = .32), self-stigma (OR = .29), negative attitudes about treatment (OR = .27), and practical barriers (OR = .34) were all associated with a lower likelihood of having sought treatment among students experiencing a problem. Of the five-factor model personality traits, only Neuroticism was associated with a higher likelihood of having sought treatment when experiencing a mental health problem (OR = 2.71). When we considered all significant predictors in a final stepwise conditional model, only self-stigma, practical barriers, and Neuroticism remained significant unique predictors. Implications for addressing barriers to treatment and encouraging treatment seeking among college students are discussed. (PsycINFO Database Record