PT Evaluation Details
AB Manager helps accrediting organizations evaluate proficiency test (PT) results in accordance with the the latest accreditation standards. Please note the following:
- Imported PT data must include the correct TNI identifiers for matrix, method (determines technology), and analyte.
- AB Manager checks PT status for the specific fields of accreditation (FOA) requested by each laboratory. An FOA is a unique combination of matrix, method (TNI code), and analyte (TNI code). Each method code includes a TNI technology (e.g., GC-MS or ICP-AES).
- By default, AB Manager uses the ‘PT by technology’ method of evaluating PT results as described in TNI 2016 V1M1 4.3.4. This approach groups PT results by matrix, analyte, and technology (rather than method). See Note 1 below.
- On the laboratory parameters page, the ‘PT-TNI’ column shows an analysis of the three most recent time intervals, including whether each PT study met the timing requirements of TNI 2016 V1M1 5.2. For example, ‘Pass-2’ indicates that the laboratory passed 2 of the most recent 3 time intervals. PT-TNI details are shown in the lab’s proficiency tab.
- The ‘PT-EPA’ column shows the date of the most recent successful PT for that exact matrix/method/analyte.
- The “FoPT” column indicates whether that specific analyte is listed on TNI’s FoPT tables (see TNI 2016 V1M1 4.1.1).
Note 1: The benefit of the ‘PT by technology’ approach is to give the laboratory ‘credit’ when similar methods (those using the same technology) are used. For example, if the lab requests accreditation for iron in non-potable water using method 6020B (method code 10156420), AB Manager will apply any and all NPW/Iron/ICP-MS results from each PT study submitted.
The ‘PT by technology’ approach may occasionally give spurious results if the laboratory is attempting to analyze more than one method that share the same technology but are on separate PT schedules. For example, the laboratory may be running 8015D GRO (10305609) using one PT provider and AK101 GRO (90015002) using another. Because the fields of accreditation share the same analyte (GRO #9408) and technology (GC-FID) the results will be mixed and analyzed as a group. In those instances, PT results may be evaluated manually using ‘search PT results’ tab.
V1M1 4.1.1
TNI publishes lists of FoPTs for which PT studies are required, called TNI FoPT Tables. These FoPT tables may be updated, as needed, by publishing revised FoPT tables on the TNI website.
V1M1 4.3.4 Reporting Requirements
Except for drinking water analytes referenced in 40 CFR 141, a laboratory may choose to analyze and report a single method to represent a technology in a single PT study for a particular analyte. If the laboratory analyzes and reports PT studies by “technology,” the score obtained for the reported method will be applied to all methods in that technology for which the laboratory seeks to obtain or maintain accreditation in that matrix.
NOTE: If a laboratory reports PT results for multiple methods using the same analytical technology, an evaluation of “not acceptable” for one method will be applied to all methods reported with that technology.
V1M1 5.2 Continued Accreditation
5.2.1 Chemical Testing, Radiochemical Testing, Asbestos, and Microbiology
5.2.1.1 The laboratory shall maintain a history of two (2) successful (acceptable scores) PT studies out of the most recent three (3) attempts for each field of accreditation specified in Section 4.1.1 for which the laboratory holds accreditation. Failure to do so may result in suspension of the affected field of accreditation. The laboratory’s accreditation for a field of accreditation may be revoked for failure of three (3) consecutive PT studies, either by failure to participate in the required PT study or due to failure to obtain acceptable results.
5.2.1.2 The laboratory shall analyze and report a PT study at least twice per year for each accreditation FoPT for which it seeks to maintain accreditation, in accordance with the following criteria:
a) The closing dates of subsequent PT study samples for a particular accreditation FoPT shall be no more than seven (7) months apart.
b) The opening date of PT study samples for a particular field of accreditation must be at least seven (7) calendar days after the closing date of a PT study for the same field of accreditation.
c) A laboratory that analyzes and reports PT study results with an opening date of subsequent PT studies for the same field of accreditation that are closer than seven (7) days from the closing date of the previous PT study are invalid for the purposes of compliance with this Standard and are not counted toward the laboratory’s PT history of the most recent three (3) attempts.
5.2.2 For WET testing: To maintain accreditation, the laboratory shall participate in one (1) WET PT study per calendar year for each accreditation FoPT that correspond to the fields of accreditation for which the laboratory is accredited.
a) This requirement can be met by annual participation in the Environmental Protection Agency (EPA) Discharge Monitoring Report-Quality Assurance (DMRQA) studies for WET, or
b) If the laboratory is not participating in an EPA DMRQA study for WET, the closing dates of subsequent PT study samples for WET testing PT studies must be no more than fourteen (14) months apart.