Abstract

MARIANI, Virginia Alcira  and  SOLA, María Ofelia. Program for external quality evaluation: differences in commercial inmunoassays of prostate-specific antigen. Acta bioquím. clín. latinoam. [online]. 2005, vol.39, n.2, pp.243-252. ISSN 0325-2957.

Due to the importance of the PSA (Prostate Specific Antigen) test the Program for External Quality Assessment (PEEC) of the FBA carried out five surveys among 200 laboratories. Five lots of lyophilized commercial serum with different degrees of PSA (ng/mL) were distributed among the participants and for each lot the Consensus Media (Mc), the Consensus Standard Deviation (SDc) and participants (N) were calculated: Lots 1, N1 = 272, Mc1 ± SDc1 = 2,6 ± 0,7; lot 2, N2=242, Mc2 ± SDc2 = 4,8 ± 1,2; lot 3, N3=128, Mc3 ± SDc3 = 8,1 ± 1,9; lot 4 N4=119, Mc4 ± SDc4 = 18,2 ± 4,5; lot 5, N5=262, Mc5 ± SDc5 = 55,7 ± 12,6. The results were useful to evaluate and compare nine commercial kits: Coat-A-Count and IMMULITE of Diagnostic Products Corporation®; IMX and AXSYM by Abbott®; ELFA by Bio-Merieux®; ELECSYS-1010 and 2010 by Roche®; ACS-180 by Bayer® and Access by Beckman®. The parameters evaluated were 1) Coefficient of Variation calculated as the quotient between the standard deviation and the media of each laboratory group using the same commercial trademark multiplied by 100 2) The Percentage of Relative Deviation (PRD) calculated as the distance between the obtained results of each laboratory and the media of each commercial equipo. The methods with the best behavior as regards the obtained CV were: AXSYM, ELFA, ELECSYS-1010, ELECSYS-2010, IMMULITE y ACCESS. Most of the participants using automatic methods, obtained better PRD in the different surveys compared to the laboratories using manual techniques. According to the test, it is not possible to compare results from laboratories using different methodologies.

Keywords : Program for External Quality Assessment; prostate specific antigen.

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