Quality Assurance (Proficiency Testing)

The Centers for Medicare and Medicaid Services (CMS) have published a brochure with questions and answers regarding CLIA required proficiency testing: http://www.cms.gov/CLIA/downloads/CLIAbrochure8.pdf [1.10MB, PDF] Excerpts from that brochure with the more frequently asked questions are also presented below. Nonwaived providers are encouraged to review this CLIA brochure. Nonwaived providers include Provider Performed Microscopy (PPM) providers.

All initial non-waived applicants for state licensure must identify the name of the proficiency testing program in which the Laboratory participates for each specialty/subspecialty and the program set for each in the initial licensure application. This information must also be provided when adding a specialty/subspecialty. Additionally, Provider Performed Microscopy (PPM) laboratories must also indicate the quality assurance methodology used for each non-waived test.

Additional information for PPMP providers


What is proficiency testing?

Proficiency testing or PT is the testing of unknown samples sent to a Laboratory by a CMS approved PT program. Most sets of PT samples are sent to participating laboratories three times per year. After testing the PT samples in the same manner as its patient specimens, the Laboratory reports its sample results back to their PT program. The program grades the results using the CLIA grading criteria and sends the Laboratory scores reflecting how accurately it performed the testing. CMS and accreditation organizations routinely monitor their laboratories’ performance.

Is PT required for all nonwaived testing?

PT is required for only the limited number of tests found in Subpart I, Proficiency Testing Programs for Nonwaived Testing, of the CLIA regulations. If your Laboratory performs any of the tests found in subpart I, you must perform PT on each of the tests. We refer to the tests listed in subpart I as “regulated” analytes.
Review the specialty, subspecialty and analytes listed and determine which specialties, subspecialties and analytes you perform in your Laboratory. Enroll in a CMS approved PT program for each of those tests.

Can I enroll in any program that offers PT?

You must enroll in a CMS approved PT program. A detailed listing of these programs with their contact information and the tests for which they are approved is available at www.cms.hhs.gov/clia; click on “PT providers”.

If I have more than one testing site, do I need to enroll in PT for each site?

PT enrollment and participation is required for each CLIA certificate; i.e., PT per certificate (excluding certificate of waiver). If you offer non-waived testing at more than one site, but the testing is all included under one certificate, you must enroll in an approved PT program(s) for all the “regulated” analytes covered under that certificate, not for each site. If you have a separate certificate for each site, you must enroll in PT for the tests performed at each site.

May I change my PT program whenever I wish as long as it is CMS approved?

You may not randomly change from one approved PT program(s) to another. Laboratories must enroll and participate in one approved program for one year before designating a different program. Laboratories should enroll in the fall for the next calendar year. However, if you apply for a new CLIA certificate mid-year or add a “regulated” specialty, subspecialty, or analyte in the middle of a year, you may change PT programs at the next PT enrollment period.

If my Laboratory is new or if I add a new “regulated” specialty, subspecialty or analyte in the middle of a calendar year, how quickly must I enroll in PT?

Laboratories operating under a new certificate and/or adding new “regulated” testing must enroll in PT as soon as possible and complete the PT for the remainder of the year.

If I perform “unregulated” testing (tests for which PT is not required), am I required to check the accuracy and reliability of those tests?

CLIA requires laboratories to take steps to assure the accuracy of testing in lieu of testing PT samples. CLIA requires that, at least twice annually, you verify the accuracy of any test or procedure that you perform that is not listed in Subpart I.

How do I verify the accuracy of the tests that do not have PT required?

A few examples of ways to check the accuracy of testing not listed in Subpart I are as follows: Split a patient’s specimen (NEVER SPLIT A PT SAMPLE) with another Laboratory that offers the same test(s). Your director should review your results and the other Laboratory’s results for acceptability.

Are there ever circumstances in PT that require my Laboratory to verify the accuracy of “regulated” tests?

Yes, there are. There are times when the PT program cannot fully evaluate your samples and you must verify accuracy (a few ways to accomplish this are listed above). You must verify the accuracy of tests for which PT is required if any of the following occur:

  • When your results are submitted to the program after the deadline and are considered a late submission, your Laboratory grade will be zero.
  • If you did not test your PT samples at all, your Laboratory grade will be zero.
  • There are instances when your grade does not reflect your performance because there was no consensus among all laboratories performing the PT sample(s). You will see this identified by the PT program as “ungradable” on your results report. You will be assigned an artificial score of “100%”, noted as “ungradable”, but that does NOT reflect your performance.

May I discuss my PT results with another Laboratory?

NEVER discuss your PT results with another Laboratory and NEVER enter into discussion with another Laboratory about their PT results before the PT event cut-off date. This activity may cause you to lose your CLIA certificate.

May I send my PT samples to another Laboratory to see if they get the same results as I do?

NEVER send your PT samples to another Laboratory even if you send your patient specimens to another Laboratory for confirmation or identification testing. (Please read the PT results sheet carefully and select “Would refer” or “Test not performed” in these instances.) Sending PT samples to another Laboratory for testing is considered PT referral and will cause serious actions to be taken against your Laboratory, your Laboratory director, and the Laboratory owner. The penalties include loss of your Laboratory’s CLIA certificate for at least one year, your director cannot direct a Laboratory for two years, and your Laboratory owner may not own or operate a Laboratory for two years. Your Laboratory’s name will be listed on the CMS Laboratory Registry on the CMS web site. Be extremely cautious NOT to send PT samples out for a “reflex” test. (A “reflex” test is a test procedure routinely added-on to a patient specimen when the test results are at a level that meets the clinician’s threshold to automatically add specific tests. This is usually done by a “standing” order.)

What do I do if I receive PT samples from another Laboratory for testing?

As soon as you identify them as PT samples, notify your inspecting agency (your accreditation organization if your Laboratory is accredited or your State agency inspectors) that you have received PT samples from another Laboratory, tell them the name of the other Laboratory and the test(s) requested, but DO NOT TEST the samples.

Do I need to keep records of my PT testing?

Yes, you must keep a copy of all your records, such as the step by step PT sample preparation and handling, all the steps taken in the testing of the sample, a copy of the PT program results form used to record and submit your PT results (includes the attestation statement), a print screen if results are entered electronically, and the PT program’s evaluation of your Laboratory’s performance, etc. These copies must be maintained for a minimum of two years from the date of the PT event. If any corrective actions are taken as a result of an unsatisfactory or unacceptable score, maintain records of these actions for two years also.

This CLIA brochure (http://www.cms.gov/CLIA/downloads/CLIA%20brochure8.pdf) [1.10MB, PDF] lists the regulated analytes beginning on page 10. Hospitals and independent laboratories are required to enroll in Proficiency Testing for all tests performed, if PT is available for the test. If PT is not available for a test, they must have a method to verify accuracy twice annually.

Laboratories operated by practitioners exclusively for diagnosis and treatment of their own patients are required to enroll only in the regulated analytes and they must perform twice annual verification of accuracy for non-regulated analytes.

Regulated Analytes: List of Nonwaived Testing for which PT is Required:


Aerobic/Anaerobic Culture & Identification Antibiotic Susceptibility Testing Direct Bacterial Antigen Detection Gram Stain
Acid Fast Stain Mycobacteriology Identification Mycobacteriology Susceptibility Testing
Culture and Identification
Presence or Absence of Parasites
Identification of Parasites
Direct Viral Antigen Detection
Viral Isolation and Identification


Syphilis Serology General Immunology
Alpha-1 Antitrypsin Alpha Fetoprotein (tumor marker) Antinuclear Antibody Antistreptolysin O Anti-Human Immunodeficiency Virus
Complement C3
Complement C4
Hepatitis B Surface Antigen (HBsAg)
Hepatitis B Core Antibody
Hepatitis Be Antigen (HBeAg)
Immunoglobulins, total:
Infectious Mononucleosis Rheumatoid Factor Rubella


Routine Chemistry
Alanine Aminotransferase
Alkaline Phosphatase
Amylase Aspartate Aminotransferase (AST or SGOT)
Bilirubin, total
Blood Gases:
Calcium, total
Cholesterol, total
Cholesterol, HDL
Creatine Kinase, total
Creatine Kinase, Isoenzyme (CK-MB) Creatinine Glucose Iron, total Lactate Dehydrogenase (LDH), total LDH Isoenzymes (LDH1/LDH2) Magnesium Potassium Sodium Total Protein Triglycerides Urea Nitrogen Uric Acid
Cortisol Free Thyroxine Human Chorionic Gonadotropin T3 Uptake Triiodothyronine Thyroid Stimulating Hormone Thyroxine, total
Blood Alcohol
Blood Lead
Gentamicin Lithium Phenobarbital Phenytoin Primidone Procainamide and Metabolite Quinidine Theophylline Tobramycin Valproic acid


Cell Identification WBC Differential Erythrocyte Count Hematocrit Hemoglobin Leukocyte Count Platelet Count Fibrinogen Partial Thromboplastin Time Prothrombin Time


ABO Group D (Rho) Typing Unexpected Antibody Detection Compatibility Testing Antibody Identification