Abstract

MARIANI, Virginia Alcira  and  SOLA, María Ofelia. Program for External Quality Assurance: Methodologyic Comparison for free T4. Acta bioquím. clín. latinoam. [online]. 2006, vol.40, n.3, pp.425-432. ISSN 0325-2957.

Due to the clinical importance in the determination of the free thyroxine (fT4) test the Program for External Quality Assurance (PEEC) of the Fundación Bioquímica Argentina (FBA) carried out three surveys among 250 laboratories. Three lots of lyophilized commercial serum with different degrees of fT4 (hg/dL) were distributed among the participants and for each lot the Consensus average (mc) and the Consensus Standard Deviation (SDc) were calculated for all the participants (n): Lots 1, n1=386, mC1 ± DSC1 = 0.6 ± 0.2; lot 2, n2=604, mC2 ± DSC2 = 1.2 ± 0.3; lot 3, n3=301, mC3 ± DSC3 = 3.2 ± 0.8. The results allowed us to make the evaluation and comparison of nine commercial kits: Coat-A-Count and IMMULITE of Diagnostic Products Corporation®; IMX and AXSYM of ABBOTT®®; ELFA of Bio-Merieux®; ELECSYS-1010 and 2010 of ROCHE®; ACS-180 of BAYER® and ACCESS of BECKMAN®. The following statistical rules were evaluated 1) Variation Coefficient (each laboratory group using the same commercial trade mark) 2) The Percentage of Relative Deviation of all the groups (DRPt) calculated as the difference between the results obtained from each laboratory and the consensus media 3) The Percentage of Relative Deviation of each commercial kit (DRPr) calculated as the difference between the results obtained from each laboratory and the media of each commercial kit. The PEEC accepts DRP ≤ 9.9%. The percentage of laboratories that are accumulated before reaching the acceptability level is 61.6%. The sequence increasing order of acceptability was 81.6% ELECSYS 2010; 70.8% ELECSYS 1010; 66.7% ACCESS; 64,9% IMX; 61.3% ELFA; 60,0% AXSYM; 57.1% ACS 180; 55.4% IMMULITE and 36.6% Coat-A-Count of DPC. The higher the accumulated percentage, the greater amount of participants will have made the analytical evaluation in conditions of acceptability of international recognition.

Keywords : Program of External Quality Assurance; free T4.

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