A multicenter evaluation of dysthyroxinemia in a defined patient cohort.

Background: In the region Limburg (The Netherlands) almost all of the five participating laboratories use a different immunoassay platform to determine thyroid stimulating hormone (TSH) and free thryoxine (FT4). With the frequent transfer of patients within the region, harmonization of test result interpretation is necessary. In this study, we investigated dysthyroxinemia classification between participating laboratories and developed procedures for improvement.

Practical application of Sigma Metrics QC procedures in clinical chemistry.

Background: Many labs have not yet selected the most appropriate Westgard Quality Control (QC) rule for each test. This is mainly due to the apparent complexity of the matter.

Methods: From the Westgard OPSpecs Charts QC planning tool and the Sigma Metrics formula's it was deduced that every Westgard rule has its own Sigma value.

Reasons for ordering laboratory tests and relationship with frequency of abnormal results.

Objective: Laboratory tests are ordered on a daily basis, even though disease probability is often very low. Abnormal results, especially mildly abnormal results, can be difficult to interpret in these circumstances. Further insights into the occurrence of abnormalities can help improve rational test ordering and test interpretation.

Correction of patient results for Beckman Coulter LX-20 assays affected by interference due to hemoglobin, bilirubin or lipids: a practical approach.

The influence of interference by hemolysis, icterus and lipemia on the results of routine chemistries may lead to wrong interpretations. On Synchron LX-20 instruments (Beckman Coulter) serum or plasma indices can be used as reliable semi-quantitative measures of the magnitude of such interference. In an article recently published in this journal, we presented the results of a multicenter study carried out in Dutch hospitals in which we determined cutoff indices for analytes above which analytically significant interference exists.

Multicenter evaluation of the interference of hemoglobin, bilirubin and lipids on Synchron LX-20 assays.

The influence of interference by hemolysis, icterus and lipemia on the results of routine chemistries may lead to wrong interpretations. The H-, I- and L-indices that can be measured by the Beckman LX-20 instrument (Beckman Coulter) in serum or plasma samples are a reliable semi-quantitative measure of the size of these interferences. A survey carried out in 16 Dutch clinical laboratories on the use of these indices demonstrated that in several of these laboratories, the influence of interferences is largely underestimated.