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Addendum 3 <br /> Quality Control Requirements for Laboratories Performing Microbiological Testing <br /> In addition to the quality control requirements outlined in Chapter 5 of the NELAC Standards , the <br /> following quality control measures shall be implemented for this Agreement. Note : "Sample" refers to <br /> samples that have been either collected or analyzed under the terms of this Agreement. <br /> 1 . All microbiological analyses must conform to the requirements for facilities , personnel qualifications <br /> equipment specifications and quality control measures discussed in AWWA Standard Methods 20th <br /> edition, section 9020. <br /> 2 . Quality Control Blanks <br /> a . If the membrane filter technique is used , the sample set(s) shall be associated with a beginning <br /> and ending filtration blank . <br /> b . The results of any blank must be < 1 CFU/ 100 mL or the associated sample results must be <br /> reported with the appropriate qualifier from Chapter 62- 160 , F . A. C . <br /> 3 . Laboratory Quality Control Duplicates <br /> a . At least 10 % of the samples (or one per test run ) shall be duplicated . <br /> b . All duplicate results shall be evaluated per method specifications using the precison criterion . <br /> The range of the transformed duplicates shall not exceed the precision criterion established by <br /> the laboratory. In the event that laboratory duplicate agreement is not observed , the laboratory <br /> must investigate the poor precision and report the results with appropriate qualifiers and/or <br /> comments . <br /> c. Field Quality Control Duplicates or Replicates - In the event that agreement ( less than or equal <br /> the laboratory established precision criterion ) is not observed between results from field- <br /> generated replicate samples , the laboratory must investigate the replicate analyses to determine <br /> that poor precision is not due to a laboratory error and report the results with appropriate <br /> qualifiers and/or comments . The laboratory shall use the analytical method specifications for <br /> precision control as a guide to evaluation of the field -generated replicate results . <br /> 4 . Colony Counts <br /> a . In addition to the requirements listed below, all analytical results shall be calculated by the <br /> procedures established in the microbiological method (s ) approved for the Agreement and listed in <br /> the planning document . <br /> b . The laboratory shall make every attempt to ensure that colony counts are in the ideal range of 20 <br /> . 60 colonies per plate . Reported values from colony plate counts outside this range shall be <br /> qualified with a " B" ( unless the reported value is from a 100 mL sample and the count is less than <br /> 20 ) . <br /> C. If all counts are above 60 , the result shall be calculated and reported from the highest dilution . <br /> This result must be reported as "estimated' . <br /> d . The laboratory shall follow the reporting requirements specified in the method for other results <br /> that are outside the ideal range ( item 5 . b . above ) <br /> e . If the sample result is "too numerous to count (TNTC )" the laboratory shall report the filtration <br /> volume with the data qualifier "T' . <br /> f. Colony counts from samples that have been verified shall be adjusted based on the verification <br /> results as specified in the analytical method approved for this Agreement and listed in the <br /> planning document . <br /> Revised 3/05 <br /> DEP Agreement No . GO 143 , Attachment H, Page 11 of 11 <br />