[Nucleic acid testing: Biomerieux Roche technology. Setting up of limits concerning temperature, volume and incubation time during the nucleic extraction step]. / Dépistage génomique viral : technique combinée biomérieux/roche. Etude des limites de tolérance des parametres températures, temps d'incubation et volumes au cours de l'extraction des acides nucléiques par le nuclisens extractor.

Nucleic acid testing is carried out in several steps: plasma pooling, nucleic acid extraction, amplification and detection. The target values of temperature, volume and incubation time are mentioned in the initial protocol without giving their limit values. The objective of this work was to determine the range of values in which the test remains positives. So we have tested: 1) the temperature and incubation time of plasma in lysis buffer (37 degrees C +/- 3 et 30 min +/- 10); 2) the influence of volume and incubation time of silica (50 mul +/- 10 et 10 min +/- 5); 3) the variation of the eluate volume after nucleic extraction. We have also studied the influence of the internal control volume variation. For each parameter the assays were performed at sensitivity limit of the technique and repeated several times. Our results showed that: 1) for all parameters evaluated the tests remain positive within a wide range of values; 2) It is not necessary to set up a sophisticated measurement process; 3) the technique is robust.