English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

BACKGROUNDInformation on interlaboratory variation and especially on methodological differences for plasma total homocysteine is lacking.METHODSWe studied 14 laboratories that used eight different method types: HPLC with electrochemical detection (HPLC-ED); HPLC with fluorescence detection (HPLC-FD) further subdivided by type of reducing/derivatizing agent; gas chromatography/mass spectrometry (GC/MS); enzyme immunoassay (EIA); and fluorescence polarization immunoassay (FPIA). Three of these laboratories used two methods. The laboratories participated in a 2-day analysis of 46 plasma samples, 4 additional plasma samples with added homocystine, and 3 plasma quality-control (QC) pools. Results were analyzed for imprecision, recovery, and methodological differences.RESULTSThe mean among-laboratory and among-run within-laboratory imprecision (CV) was 9.3% and 5.6% for plasma samples, 8.8% and 4.9% for samples with added homocystine, and 7.6% and 4.2% for the QC pools, respectively. Difference plots showed values systematically higher than GC/MS for HPLC-ED, HPLC-FD using sodium borohydride/monobromobimane (however, for only one laboratory), and EIA, and lower values for HPLC-FD using trialkylphosphine/4-(aminosulfonyl)-7-fluoro-2,1,3-benzoxadiazole. The two HPLC-FD methods using tris(2-carboxyethyl) phosphine/ammonium 7-fluoro-2,1,3-benzoxadiazole-4-sulfonate (SBD-F) or tributyl phosphine/SBD-F, and the FPIA method showed no detectable systematic difference from GC/MS.CONCLUSIONSAmong-laboratory variations within one method can exceed among-method variations. Some of the methods tested could be used interchangeably, but there is an urgent need to improve analytical imprecision and to decrease differences among methods.

Comparison of Plasma Total Homocysteine Measurements in 14 Laboratories: An International Study