Microbiology-PTM-OMA_Modules_1-5

Replicates for Composite Test Portions

• Compositing is the combining of individual test portions for the  purpose of performing a single enrichment for cost savings when the  probability of any individual test portion being positive is very low • For example, laboratories may composite 15 individual 25‐g test portions into  a 375 g composite test portion • The composite enrichment must be positive if even one of the individual 25‐g  test portions is positive • Same needle now in a bigger haystack – must now detect one target cell in  375 g • Candidate method composite test portions are compared to  reference method individual (25 g) test portions