Standardisation of quantitative data obtained by several types of rheumatoid factor test was achieved by the use of a reference serum preparation. Interlaboratory comparability improved for the latex fixation test, the Waaler-Rose test, the IgM RF test by an enzyme linked immunosorbent assay (ELISA), and for the antiperinuclear factor test. Use of a common method and latex preparation was not s...

Many different thermal, optical, and thermal/optical carbon analysis methods for organic carbon (OC), elemental carbon (EC) or black carbon (BC) have been applied throughout the world to evaluate visibility and the Earth’s radiation balance. Dozens of intermethod and interlaboratory comparison studies have been conducted. Several of these studies are catalogued and summarized here. BC or EC con...

The results have been compared of microbiological and radioisotope dilution (RID) assay of serum vitamin B12 by participants in national interlaboratory trials in Britain. There was wide variation between the individual participants, especially marked in the L. leichmannii microbiological assay and in the RID methods, whereas excellent correlation, reproducibility, and recovery were obtained in...

A potential low magnetic moment standard reference material (SRM) was studied in an interlaboratory comparison. The mean and the standard deviation of the saturation moment m s, the remanent moment m r, and the intrinsic coercivity H c of nine samples were extracted from hysteresis-loop measurements. Samples were measured by thirteen laboratories using inductive-field loopers, vibrating-sample ...

Carbonaceous aerosols are present in many workplace and environmental settings. Some of these aerosols are known or suspect human carcinogens and have been linked to other adverse health effects. Exposure to diesel exhaust is of particular concern because it has been classified as a probable human carcinogen and use of diesel-powered equipment is widespread in industry. Because previously used ...

BACKGROUND Insulin-like growth factor 1 (IGF-1)(7) is a key mediator of growth hormone (GH) action and a well-characterized biomarker of GH abuse. Current immunoassays for IGF-1 suffer from poor concordance between platforms, which makes comparison of results between laboratories difficult. Although previous work has demonstrated good interlaboratory imprecision of LC-MS/MS methods when plasma ...