Determination of iohexol and iothalamate in serum and urine by capillary electrophoresis.

Estimation of glomerular filtration rate (eGFR) is essential to assess kidney function. Iodine-containing contrast agents detection by HPLC has been proposed as a safe alternative for inulin or radioactive compounds. However, HPLC is a time-consuming and labor-intensive method.

A Progress Report of the IFCC Committee for Standardization of Thyroid Function Tests.

Background: The IFCC Committee for Standardization of Thyroid Function Tests aims at equivalence of laboratory test results for free thyroxine (FT4) and thyrotropin (TSH).

Objectives: This report describes the phase III method comparison study with clinical samples representing a broad spectrum of thyroid disease. The objective was to expand the feasibility work and explore the impact of standardization/harmonization in the clinically relevant concentration range.

Dual-wavelength recording, a simple algorithm to eliminate interferences due to UV-absorbing substances in capillary electrophoresis.

Analytical interferences have been described due to the presence of various exogenous UV-absorbing substances in serum. Iodine-based X-ray contrast agents and various antibiotics have been reported to interfere with interpretation of serum protein pherograms, resulting in false diagnosis of paraproteinemia. In the present study, we have explored the possibility of measuring UV absorbance at two distinct wavelengths (210 and 246 nm) to distinguish between true and false paraproteins on a Helena V8 clinical electrophoresis instrument.

Long-term stability of laboratory tests and practical implications for quality management.

Background: Long-term stability of analytical performance is required for adequate patient management. We investigated the use of patient data to document test stability, and the relevance of observed instabilities on a surrogate medical outcome. We used multiyear patient and internal quality control (IQC) data from two laboratories for tests to monitor chronic kidney and thyroid disease.

"Good samples make good assays" – the problem of sourcing clinical samples for a standardization project.

Clinical samples are the cornerstone in all aspects related to in vitro diagnostic testing. They are particularly valuable in the process of establishing/validating metrological traceability, because they eliminate commutability issues potentially associated with artificial calibrators. Therefore, they are essential for IFCC standardization projects.

IFCC international conventional reference procedure for the measurement of free thyroxine in serum: International Federation of Clinical Chemistry and Laboratory Medicine (IFCC) Working Group for Standardization of Thyroid Function Tests (WG-STFT)(1).

The IFCC Working Group for Standardization of Thyroid Function Tests proposes a candidate international conventional reference procedure (RMP) for measurement of the amount-of-substance concentration of free thyroxine in plasma/serum at physiological pH 7.40 and temperature (37.0°C).

Standardization activities in the field of thyroid function tests: a status report.

Background: Laboratory testing is an essential tool for diagnosis and management of thyroid diseases. However, the current status of standardization hampers the interchangeability of results. To improve this situation, the Working Group for Standardization of Thyroid Function Tests was established.

Traceability to a common standard for protein measurements by immunoassay for in-vitro diagnostic purposes.

Background: There is a lot of confusion about the meaning of "measuring a protein in biological fluids" for in-vitro diagnostic purposes. This is due to a lack of understanding of metrological concepts and of acceptance of a pragmatic metrological concept for mixture analysis.

Methods: We describe the metrological concepts that apply to measurement of proteins.