Proficiency Testing FINAL REPORT Check sample program 16CSP02 February 2016

Transcription

1 Proficiency Testing FINAL REPORT Check sample program 16CSP2 February 216 Proficiency Testing Provider Certificate Number Program Coordinator: Ingrid Flemming IFM Quality Services Pty Ltd PO Box 877 Ingleburn NSW 26 Australia Tel: +61 () Fax: +61 () Samples Dispatched: 12 October 21 Results Due: 29 February 216 Report Issued: 21 March 216 IFM Quality Services Pty Ltd Page 1

2 Operational Summary NUMBER OF ROUNDS AND FREQUENCY OF TESTING 12 samples are provided per annum, sent in 2 consignments, each containing 6 consecutive rounds. 1 sample is tested each month. SAMPLE PRESENTATION AND RECONSTITUTION Samples were presented in freeze-dried vials. Prior to testing, samples must be reconstituted in accordance with the instructions provided. The final sample volume is 1 ml. This is to be treated as the neat sample. ASSURANCE OF SAMPLE INTEGRITY Samples were prepared by the Support Division of IFM Quality Services. Homogeneity and stability tests were conducted by the Testing Division of IFM Quality Services. On production, each sample batch is subjected to a homogeneity evaluation. Following initial acceptance, retained samples undergo regular monitoring to confirm ongoing homogeneity and fitness for purpose. All required homogeneity criteria were met. METHOD OF DISPATCH All samples were sent via express national/international courier. Insulated packaging and a cooling agent were used to assist in protection against temperature fluctuations during transit. ASSESSMENT PROCEDURE Please refer to IFM s Policies on the assessment of microbiological PTP results: DISPUTE PROCEDURE Participants wishing to dispute their assessment, or appeal an evaluation on other grounds should submit their appeal in writing to the program coordinator. Please refer to for the detailed policy. CONFIDENTIALITY The identity of participants and any identifying information supplied by participants is treated as confidential. Appropriate policies and procedures have been put into place to ensure this confidentiality is maintained. Please refer to for the detailed policy. TEST INSTRUCTIONS Instructions applicable to this testing round may be found at: INDIVIDUAL RESULTS Should individual test results be required, these will be provided upon request. IFM Quality Services Pty Ltd Page 2

3 Available Tests Enumerative Tests (cfu/1ml) E. coli Coliform Thermotolerant (Faecal) coliform Clostridium (vegetative) Coagulase positive Staphylococcus spp. Enterococcus spp. Faecal Streptococcus Pseudomonas aeruginosa Pseudomonas spp. Mould Yeast (cfu/ml) Plate Plate (21 degrees) Assessment Criteria For enumerative tests, robust statistics are applied in order to determine a Z score for each result. Acceptable Z scores are Z <3.. Whenever possible non-numeric results are assessed by applying simple pass/fail assessments without issue of Z scores. Variations to the normal assessment procedure will be detailed in the discussion. Participation Summary 9 organisations enrolled 67 organisations participated 29 sets of results were submitted 92 individual test results were received 881 results were assessed results were not assessed results were assessed as outliers Sample Content RM Number Organism Name (IFM Number) RM8 Staphylococcus aureus (3) RM127 Pseudomonas aeruginosa () RM133 Candida albicans (21) RM132 Escherichia coli (2) RM1 Aspergillus niger (23) RM17 Enterobacter cloacae (22) IFM Quality Services Pty Ltd Page 3

4 Discussion PSEUDOMONAS SPP. COUNT Statistics were not calculated for this test because too few results were submitted. All submitted results were considered to be within an acceptable range of each other and also IFMs monitoring data. All participants received pass assessments. COLIFORM, E. COLI AND PLATE COUNT 1 laboratory with 2 participants submitted results for coliform, E. coli and plate counts. To prevent this laboratory from creating a bias in statistical calculations only part1 s results were included in the statistical calculations. Ensuring that 1 laboratory s results do not affect statistical calculations is an important consideration. A high proportion of similar or identical results from 1 laboratory can: skew the statistical calculations such that laboratories with otherwise acceptable results receive poor Z-scores. increase the NIQR such that Z-scores do not adequately reflect participants /laboratories abilities. make the analysis of long term trends in performance difficult when some rounds were biased, whilst others were not. IFM is currently reviewing its procedures for the calculation of statistics when a large proportion of results are submitted by a single or small number of laboratories. Statistical calculations and histograms for the 3 below-listed data-handling methods, when applied to the results for E. coli, coliform and plate count, are shown on pages and 6. Method 1 (Represented by the sum of Red, Blue and Green bars in the histograms) This method includes all submitted results in the statistical calculations. It is most affected when a single, or small number of laboratories submit a high proportion of the total number of results. Method 2 Method 2 is the method currently being employed to reduce the bias of multiple results from a single laboratory. It involves excluding participants 2 to n when the results are determined to significantly affect the statistics. However, this method is limited in that other laboratories with multiple results may then cause a statistical bias. For this method, Green bars represent those results excluded from the statistical calculations, whilst Blue and Red bars represent those results included in the statistical calculations. Method 3 This method uses only one result from each laboratory for the statistical calculations, thereby giving each laboratory an equal influence. For this method, Blue bars represent those results included in the statistical calculations. Regardless of the method employed, all results will be assessed against the statistical calculations of that IFM Quality Services Pty Ltd Page

5 method. In addition to the treatment of results when laboratories submit multiple results, IFM is also reviewing its methods for calculating the robust mean and standard deviation. Participants are invited to comment on both matters CSP2 Coliform Count Method: 1 Method: 1, 2 Method: 1, 2, Count (log(cfu/1 ml)) 1CSP2 Coliform Count (log(cfu/1 ml)) Method 1 Method 2 Method 3 Median NIQR Acceptable High Acceptable Low Statistically Acceptable Range CSP2 E. coli Count Method: 1 Method: 1, 2 Method: 1, 2, Count (log(cfu/1 ml)) 1CSP2 E. coli Count (log(cfu/1 ml)) Method 1 Method 2 Method 3 Median NIQR Acceptable High Acceptable Low Statistically Acceptable Range CSP2 Plate Count Method: 1 Method: 1, 2 Method: 1, 2, Count (log(cfu/1 ml)) 1CSP2 Plate count (log(cfu/1 ml)) Method 1 Method 2 Method 3 Median NIQR Acceptable High Acceptable Low Statistically Acceptable Range IFM Quality Services Pty Ltd Page

6 Results CLOSTRIDIUM (VEGETATIVE) AND COAGULASE POSITIVE STAPHYLOCOCCUS SPP. COUNTS Below Detection Limit False Positive Not Assessed Clostridium spp. Count (vegetative) (cfu/1ml) Coagulase positive Staphylococcus spp. Count Coagulase positive Staphylococcus spp. Count (cfu/1ml) - Log Values Number of Results Analysed 2 Quartile Quartile IQR.383 NIQR.266 Median 3.68 Median + (3.*NIQR).16 Median - (3.*NIQR) Statistically Acceptable Range 1.62 Result (cfu/1ml) -Log Values IFM Quality Services Pty Ltd Page 6

7 Results COLIFORM, THERMOTOLERANT (FAECAL) COLIFORM AND E. COLI COUNTS Coliform Count Coliform Count (cfu/1ml) - Log Values Number of Results Analysed 129 Quartile Quartile IQR.389 NIQR.288 Median 3.9 Median + (3.*NIQR).82 Median - (3.*NIQR) 3.6 Statistically Acceptable Range 1.79 Result (cfu/1ml) -Log Values Thermotolerant (Faecal) Coliform Count Thermotolerant (Faecal) Coliform Count (cfu/1ml) - Log Values Number of Results Analysed 87 Quartile Quartile IQR.718 NIQR.239 Median 3.1 Median + (3.*NIQR).779 Median - (3.*NIQR) Statistically Acceptable Range 2.89 Result (cfu/1ml) -Log Values E. coli Count E. coli Count (cfu/1ml) - Log Values Number of Results Analysed 128 Quartile Quartile IQR.33 NIQR.319 Median 3.8 Median + (3.*NIQR).277 Median - (3.*NIQR) Statistically Acceptable Range 1.99 Result (cfu/1ml) -Log Values IFM Quality Services Pty Ltd Page 7

8 Results ENTEROCOCCUS SPP. AND FAECAL STREPTOCOCCUS SPP. COUNTS Below Detection Limit False Positive Enterococcus spp. Count (cfu/1ml) Not Assessed Below Detection Limit False Positive Faecal Streptococcus spp. Count (cfu/1ml) Not Assessed IFM Quality Services Pty Ltd Page 8

9 Results PSEUDOMONAS AERUGINOSA AND PSEUDOMONAS SPP. COUNTS Pseudomonas aeruginosa Count Result (cfu/1ml) -Log Values Pseudomonas aeruginosa Count (cfu/1ml) - Log Values Number of Results Analysed 6 Quartile Quartile IQR.217 NIQR.1866 Median Median + (3.*NIQR) 3.31 Median - (3.*NIQR) Statistically Acceptable Range Pseudomonas spp. Count Result (cfu/1ml) -Log Values IFM Quality Services Pty Ltd Page 9

10 Results YEAST AND MOULD COUNTS Yeast Count Result (cfu/1ml) -Log Values Yeast Count (cfu/1ml) - Log Values Number of Results Analysed 13 Quartile Quartile IQR.16 NIQR.1117 Median 3.1 Median + (3.*NIQR) 3.76 Median - (3.*NIQR) 3.7 Statistically Acceptable Range Mould Count Result (cfu/1ml) -Raw Values 216. Mould Count (cfu/1ml) - Raw Values Number of Results Analysed 13 Quartile Quartile 3 1. IQR 63. NIQR Median 9. Median + (3.*NIQR) Median - (3.*NIQR) -2.8 Statistically Acceptable Range IFM Quality Services Pty Ltd Page 1

11 Results PLATE COUNTS Plate Count Plate Count (cfu/ml) - Log Values Number of Results Analysed 132 Quartile Quartile IQR.286 NIQR.16 Median 2.31 Median + (3.*NIQR) Median - (3.*NIQR) Statistically Acceptable Range.931 Result (cfu/ml) -Log Values Plate Count 21 degrees Plate Count 21 degrees (cfu/ml) - Log Values Number of Results Analysed 6 Quartile Quartile IQR.391 NIQR.2662 Median Median + (3.*NIQR) Median - (3.*NIQR) Statistically Acceptable Range 1.62 Result (cfu/ml) -Log Values IFM Quality Services Pty Ltd Page 11

12 End of Report IFM Quality Services Pty Ltd Page 12