Interlaboratory study on the preparation and use of standard samples with F-specific RNA-bacteriophages
Ringonderzoekingen betreffende de bereiding en het gebruik van standaard monsters met F-specifieke RNA-bacteriofagen
Schijven JF, van Dommelen JA, Havelaar AH, Bahar M, Mooijman KA
RIVM Report 281008012
An interlaboratory study was performed to investigate the feasibility of producing and distributing reference samples of F-specific RNA-bacteriophage MS2. A titrated suspension of MS2 was distributed deep-frozen to 32 different laboratories throughout the world and analysed in four subsequent trials at approximately 3 month intervals. Analysis of the production batch by the organising laboratory before distribution indicated that the phages in the reference material were randomly distributed. The data from the participating laboratories indicated random distribution within vials. However, overdispersion between vials was found quite often. It was shown that the results for vials from different boxes and for different trials were significantly different within several laboratories. Stability of the reference material could reasonably be assumed in view of the results with a different preparation of MS2 that was shown to be perfectly stable for more than a year in one laboratory. Experimental conditions were not completely under control in several laboratories strongly indicating that the enumeration technique of F-specific RNA-bacteriophages according to ISO 10705-1 (1995) needs further standardisation.