Section 465.200  Proficiency Testing Samples (PTs)

a)         An environmental laboratory is required to participate in proficiency testing samples (PTs) analyses for each analytical parameter or method for which it seeks or wishes to maintain certification in accordance with the certification procedures of Section 465.130(c), the certification renewal procedures of Section 465.140(a), and the quality assurance requirements contained in Subpart B of this Part. 

b)         Heterotrophic plate count and coliform Microbiological Water Supply (WS) PT samples shall be analyzed annually (every 12 months). Cryptosporidium PT samples shall be analyzed every four to six months.  PT samples shall be analyzed in the same manner as routine samples. The laboratory shall document that the analyst analyzing any PT sample is a laboratory employee who routinely analyzes drinking water compliance samples.

c)         Laboratories shall acquire the PT sample from a provider acceptable to TNI.

d)         For methods used to test the presence or absence of an organism in a sample, each set shall contain 10 samples, all shipped at the same time in a lyophilized, dehydrated or aqueous state. The set shall include samples, in various combinations, that contain total coliforms, fecal coliforms, E. coli, non-coliforms, and at least one blank. Each set shall be used only with a single analytical method. For a PT result to be acceptable, the laboratory shall have no false negative results and no more than one false positive result for each set.

e)         For quantitative methods, each set shall contain one sample. For a PT to be acceptable, the laboratory result shall be statistically acceptable as determined by the PT provider.

f)         PT samples must be analyzed and reported within the PT provider's deadline.  The PT provider shall submit the laboratory's results and acceptable ranges to the Department.  No fee shall be charged to the Department for the analyses.

g)         In the event of a failed or unacceptable PT set as defined in 465.200(d), the laboratory must request a quick turn-around PT from the provider.

(Source:  Amended at 46 Ill. Reg. 19150, effective November 17, 2022)