EQUAL-qual: a European program for external quality assessment of genomic DNA extraction and PCR amplification.
BACKGROUND
Despite the rapid transition into routine clinical practice of molecular techniques based on PCR, external quality assessment (EQA) is still not widely available. The European Union and European Communities Confederation of Clinical Chemistry have supported the EQUAL project as a series of 3 different EQA programs for the assessment of molecular methods independently from analytes. We present the results from the EQUAL-qual program designed to evaluate the analytical aspects of DNA analysis by means of a conventional qualitative PCR experiment.


METHODS
The EQUAL-qual program provided DNA, blood samples, and primer sets to participant laboratories to assess DNA extraction and PCR amplification. We have developed statistical procedures to identify laboratories performing poorly in DNA extraction (quality and quantity), PCR efficiency, and data interpretation after electrophoresis.


RESULTS
An application to participate was obtained from 213 laboratories (from 25 countries), and 175 (82%) of laboratories submitted results for assessment. Questionable results in terms of quality and/or quantity of DNA derived from blood extractions were returned by 27% of laboratories (46 of 166). PCR efficiency showed high variability, with 3% of laboratories (5 of 163) showing a consistently low rate of amplification and 10% (18 of 175) not reporting the expected number of bands of the amplified targets.


CONCLUSIONS
The results showed considerable variability in all phases of the experiment. The approach confirms the validity of EQA as a method for evaluating analytical aspects of PCR-based tests.
Orlando
Claudio
C
Department of Clinical Physiopathology, University of Florence, Florence, Italy.
Verderio
Paolo
P
Maatman
Ronald
R
Danneberg
Jan
J
Ramsden
Simon
S
Neumaier
Michael
M
Taruscio
Domenica
D
Falbo
Vincenzo
V
Jansen
Robert
R
Casini-Raggi
Claudia
C
Malentacchi
Francesca
F
Marubini
Ettore
E
Pizzamiglio
Sara
S
Vernelen
Kris
K
Libeer
Jean-Claude
JC
Palicka
Vladimir
V
Pazzagli
Mario
M
D019411:Clinical Laboratory Techniques / Q000592:standards*; D004247:DNA / Q000097:blood* / Q000302:isolation & purification*; D005062:European Union; D015894:Genome, Human; D006801:Humans; D008297:Male; D016133:Polymerase Chain Reaction / Q000592:standards*; D011786:Quality Control
D004247:DNA