Comprehensive assessment of biotin interference in immunoassays.

BACKGROUND: Biotinylated antibodies and analogues are currently used in many immunoassays while biotin is widely used as a dietary supplement. Thus, biotin interference is an emerging issue for clinical laboratories. METHODS: Various concentrations of biotin solutions were prepared using pooled patient serum samples. All analytes were measured by sandwich or competitive immunoassay on the Roche Cobas 8000 e602 platform. RESULTS: Some of the sandwich immunoassay results were falsely decreased to different extents by different biotin levels, while some of the competitive immunoassay results were falsely increased. The most notable false reductions were in high-sensitivity troponin T, thyroid-stimulating hormone, and follicle-stimulating hormone results, while the most notable false increases were in triiodothyronine and vitamin D results. Other immunoassay results were also affected to some extent by biotin interference. CONCLUSIONS: Biotin can interfere in immunoassays and result in aberrant test results. Clinicians should use caution in interpreting abnormal results in patients who ingest biotin.

Cardiac Troponin Is a Predictor of Septic Shock Mortality in Cancer Patients in an Emergency Department: A Retrospective Cohort Study.

BACKGROUND: Septic shock may be associated with myocardial damage; however, the prognostic value of cardiac enzymes in cancer patients with septic shock is unknown. In this study, we evaluated the prognostic significance of cardiac enzymes in combination with established prognostic factors in predicting the 7-day mortality rate of patients with septic shock, and we constructed a new scoring system, Septic Oncologic Patients in Emergency Department (SOPED), which includes cardiac enzymes, to predict 7-day mortality rates. METHODS AND FINDINGS: We performed a retrospective cohort study of 375 adult cancer patients with septic shock who visited the emergency department of a comprehensive cancer center between 01/01/2004 and 12/31/2013. The 7-day and 28-day mortality rates were 19.7% and 37.6%, respectively. The creatine kinase myocardial band fraction and troponin-I were significantly higher in patients who died in ≤7 days and ≤28 days than in those who did not. In Cox regression models, troponin-I >0.05 ng/mL plus Predisposition, Infection, Response, and Organ Failure (PIRO2011) or Mortality in Emergency Department Sepsis (MEDS) score was a significant predictor of survival for ≤7 days. With our new SOPED scoring system, the receiver operating characteristic area under the curve was 0.836, higher than those for PIRO2011 and MEDS. CONCLUSIONS: Troponin-I >0.05 ng/mL was an important predictor of short-term mortality (≤7 days). The SOPED scoring system, which incorporated troponin-I, was more prognostically accurate than were other scores for 7-day mortality. Large multicenter studies are needed to verify our results and prospectively validate the prognostic performance of the SOPED score.