In 2004, EPA completed the report for the interlaboratory validation of EPA Methods 1680 (LTB/EC) and 1681 (A1) for fecal coliforms in sewage sludge (biosolids) (EPA 821-B-04-007). In 2005 (FR 70:48256) EPA proposed these methods for use in sewage sludge. As a part of the proposal, EPA also published the results of a three laboratory interlaboratory holding time study using these methods to determine whether sewage sludge samples could be held for 24 hours without significant change in bacterial densities for these analytes (Reference 8.1, EPA-821-R-04-029). Between the proposal and the final rule, EPA conducted a more extensive (23 laboratory) holding time study to confirm the results from the preliminary study in a wider variety of sewage sludge matrices (2006, Reference 8.2, EPA-821-R-07-003). The methods and the 24 hour holding time for certain media and sewage sludge treatment type combinations were promulgated in 2007 (FR 72:14220). In addition to the holding time study, culture data for the false positive and false negative confirmation rates for these two media were collected during the 2006 study but not statistically analyzed at that time. This report presents the statistical assessment of false positive and false negative confirmation rates for Methods 1680 and 1681 in sewage sludge samples analyzed during the U.S. Environmental Protection Agency's (EPA's) second sewage sludge holding time study (2006, Reference 8.2).