Functional vitamin B12 deficiency: Improving methylmalonic acid reference intervals in urine.

Background-aim: Most laboratory requests focus on the detection of possible vitamin B12 deficiency. In this context, methylmalonic acid (MMA) is reported as the best biomarker. The aim of our study was to establish the biological reference interval for MMA in urine, and assess the influence of age, sex, and vitamin B12 status on MMA concentrations.

Challenges in the diagnosis of hypervitaminemia B12. Interference by immunocomplexes.

Background-aim: High vitamin B12 concentrations are considered a common finding in clinical practice. Thanks to immunoassay accessibility, vitamin B12 has become a usual test in routine health checkups. However, these analytical methods usually present antibody-mediated interferences.

Thyroid panel reference intervals in healthy children and adolescents: A Spanish cohort.

Objectives: In children, thyroid hormones are essential for correct physical and neurological development. The recommended process for defining reference intervals (RIs) is the direct approach; however, indirect methods are an effective alternative. This study aimed to explore age- and sex-dependent relationships between serum concentrations of thyroid hormones in a large population-based cohort of healthy Spanish Caucasian children and calculate RIs.

Optimization of the thyroid panel for diagnostic purposes: Thyrotropin cut-off values for the reflex addition of free thyroxine.

Background-aim: Measurement of serum thyrotropin is currently the recommended test for the screening of thyroid dysfunction, while serum free thyroxine is kept as a reflex test. In our laboratory, the strategy followed in adult individuals from Primary Care includes a 'safety margin' for requests with a thyrotropin ≤1.0 or ≥4.

Assessment of a laboratory critical risk result notification protocol in a tertiary care hospital and their use in clinical decision making.

Introduction: Communication of laboratory critical risk results is essential for patient safety, as it allows early decision making. Our aims were: 1) to retrospectively evaluate the current protocol for telephone notification of critical risk results in terms of rates, efficiency and recipient satisfaction, 2) to assess their use in clinical decision making and 3) to suggest alternative tools for a better assessment of notification protocols.

Materials And Methods: The biochemical critical risk result notifications reported during 12 months by routine and STAT laboratories in a tertiary care hospital were reviewed.