PROFICIENCY TESTING

Effective Date: 
Tue, 05/01/2012
Reviewed: 
Tue, 01/10/2017
Policy: 

PURPOSE

The role of the proficiency test has traditionally been that of an external quality assurance check. In addition, proficiency testing performance is an assessment tool for determining regulatory compliance. The following is a list of general standards to follow in all proficiency testing, as well as a guideline to evaluate and correct problems identified throughout the proficiency testing process.

Procedure: 

GENERAL GUIDELINES

• For each testing event, inspect all PT (Proficiency Testing) materials upon receipt for completeness and damages, then refrigerate until used.

• Analyze PT specimens according to patient protocols at all times throughout the process. In other words, if a patient specimen is routinely tested only once, then do the same with the PT specimens: test only one time. If a PT specimen gives a “critical” value, then it is acceptable to repeat the test, as you would with patient results. Testing of proficiency samples should be rotated among all laboratory staff performing patient testing.

• Transcribe the results to the data sheet from the worksheet. Worksheets can be made by photocopying the blank data sheets provided by the PT provider.

• The Laboratory Supervisor should review the data sheet, as well as inspect the worksheets and tapes for clerical and transcription errors. Inspect control values to ensure that no results are reported with unacceptable quality control, as you would when patient results are generated.

• The Laboratory Director or Technical Consultant should sign and date the data sheet, and all staff performing the testing should sign in the attestation spaces provided on the data sheet.

• The completed data sheets are photocopied for documentation purposes before mailing. The mail date is noted on the laboratory copy.

• Retain a copy of all data sheets, attestation sheets, worksheets, and instrument printouts for two years.

• lf results are entered electronically to the PT provider’s website; print a copy of the results entry. Inspect it for errors before submitting the results. Keep this copy with the worksheets. Sign the attestation sheet provided and retain with these records these are to be made available for inspection by the surveyor.

ASSESSMENT OF THE PROFICIENCY TESTING REPORT

Generally, satisfactory performance criteria are a minimum score of 80% for all analytes. For analytes in the same specialty, the scores are averaged to obtain the overall specialty score. An unsatisfactory PT performance occurs when there is a failure in one event. Usually, there are three scheduled testing events each year. An unsuccessful PT performance is obtained if there are two consecutive PT event failures or two out of three PT event failures.

If repeated analyte/ specialty scores indicate unsuccessful performance, the lab is at risk of losing the ability to continue testing of that analyte or that specialty.

Initially, both the testing personnel and the Laboratory Supervisor should review the PT scores, and if all are satisfactory, the forms are signed and dated. In addition to ensuring that all results are found to be satisfactory, look for any bias in your facility’s results against those of the reporting group. If results are consistently outside 2 SDI or are consistently on one side of the mean, it may indicate a gradual long term trend and test instability and further investigation may be necessary. The Laboratory Director also must sign the forms as reviewed, and reports are kept in the Proficiency Testing Manual.

If PT results for analytes are found to be unacceptable, the following steps should be taken:

1. Check your original documentation for discrepancies, including transcription, transposition, method coding, or PT program errors.

2. Check testing records for technical processing errors, including misidentification of specimen, misinterpretation of results, results mistakenly reported outside the reportable range, or when quality control was unacceptable.

3. Document the causes and the corrective action taken to prevent these events from happening in the future.

4. If the reasons for the errors are still not apparent, evaluate the test systems affected, including the instruments themselves, problems with calibration and linearity, and problems with specimen integrity and reconstitution.

5. Evaluate the test applications prior to the time of testing to include maintenance, controls, temperature and stability of reagents.

6. If possible, retest the proficiency testing samples, which may have been frozen if applicable. If the specimen results are now found to be acceptable:

a. If one test or specimen was affected, it was most probably a "random” analytical error, due to aliquot evaporation, pipetting or dilution error, or instrument instability or power surge.

b. If two or more erroneous results were previously reported and biased in the same direction, it is referred to as a “short—term systematic analytical error" due to improper instrument maintenance, reagent deterioration or improper calibration.

7. If the above reasons explain the unsuccessful events, the patient reports results at that time should be evaluated to determine if any patients could have been clinically compromised. Document this, take corrective action and notify the ordering physician.

8. If the results on retest are not within range, look for a more "long term systematic error." If possible, obtain a new set of specimens from the PT provider to rule out problems with the PT material itself. If this is not possible, other long term systematic errors may include:

a. Bad calibration - you may need to recalibrate

b. Repetitive procedural error – re-read procedure and re-educate staff

c. Infrequent performance of test - retrain the staff or discontinue testing

d. Major instrument malfunction - call the service representative

Again, check the effect of these problems on any patient results that may have been reported, to determine the clinical significance of any discrepancies. Take appropriate corrective action, and document how this could be prevented from happening in the future. The physician or attending nurse should also be notified of any discrepancies to patient’s clinical picture. Testing should be suspended for any analyte in question until corrective action is taken and the Laboratory Supervisor and Director are confident of accurate patient testing.

Document all problems in proficiency testing. A Quality Assessment review should be performed and documented to ensure quality patient testing.

The Laboratory Staff and Director should review all PT scores and corrective action documentation, and sign and date them. Corrective action should be documented on the PT score sheet as well as the Quality Assessment review for complete documentation.