Updating proficiency testing regulations

Aug. 22, 2019
A look at the proposed rule.

After years of data gathering and deliberation, the Centers for Medicare and Medicaid Services (CMS) issued a proposed rule updating proficiency testing regulations related to analytes and acceptable performance. It is the first major change proposed for clinical proficiency testing performance since 2003, when alterations to grading challenges were finalized. 

The public comment period on the proposed rule closed in June 2019. While it may take time for the agency to dissect and consider the 107 comments received into a final regulation, there are several trends that clinical laboratories may want to note.

Defining proficiency testing needs for microbiology

To help microbiology laboratories determine the type of proficiency testing needed, the proposed rule would divide testing into categories within each microbiology subspecialty: Bacteriology, mycobacteriology, mycology, parasitology, and virology. This change would remove the current listing of types of services for microbiology subspecialties. The intent of this change, should it be finalized, is to reflect better current microbiology practices and allow for new technologies to be incorporated more readily.

Bacteriology categories for which proficiency testing would be required, include:  

  • Gram stain including bacterial morphology; direct bacterial antigen detection; 
  • bacterial toxin detection; 
  • antimicrobial susceptibility or resistance testing on select bacteria; 
  • detection and identification of bacteria (including detection of growth or no growth in culture media or identification of bacteria to the highest level that the laboratory reports results on patient specimens). 

Mycobacteriology categories for which proficiency testing would be required, include:

  • Acid-fast stain;
  • detection and identification of mycobacteria (including one of the following: Detection of growth or no growth in culture media or identification of mycobacteria; and antimycobacterial susceptibility or resistance testing).

Mycology categories for which proficiency testing would be required, include:  

  • Direct fungal antigen detection;
  • detection and identification of fungi and aerobic actinomycetes (including one of the following: Detection of growth or no growth in culture media or identification of fungi and aerobic actinomycetes; and antifungal  susceptibility or resistance testing). 

Parasitology categories for which proficiency testing would be required, include: 

  • Direct parasite antigen detection;
  • detection and identification of parasites (including one of the following: Detection of the presence or absence of  parasites or identification of parasites). 

Virology categories for which proficiency testing would be required, include:

  • Viral antigen detection;
  • detection and identification of viruses;
  • antiviral susceptibility or resistance testing. 

Among the public comments, some suggested that the proposed use of “detection of growth or no growth in culture media” needed clarification. Two examples of how the definition of “growth/no growth” could be misconstrued included urine colony count and a PCR assay reporting bacterial vaginitis from yeast infections. Instead, some recommended that “presence or absence of bacteria without identification” is a more universal descriptor. Others requested clarification on the acceptable use of molecular methods in identification.

Types of organisms included in proficiency testing

Current regulations list specific organisms for proficiency testing. The proposed rule suggests outlining more general types of organisms appropriate for each microbiology subspecialty. This is intended to allow flexibility in determining which samples laboratories might receive for proficiency testing. 

Under bacteriology, sample sources would include, as appropriate, gram-negative bacilli, gram-positive bacilli, gram-negative cocci, gram-positive cocci. Also, the current general listing of types of organisms would continue.

Under mycobacteriology, annual proficiency program content would include Mycobacterium tuberculosis complex and Mycobacterium other than tuberculosis, if appropriate for the sample source.

Under mycology, the required content would include yeast or yeast-like organisms, molds that include dematiaceous fungi, dermatophytes, dimorphic fungi, hyaline hyphomycetes, mucormycetes, and aerobic actinomycetes.

Under parasitology, annual content would include intestinal parasites, blood and tissue parasites, as appropriate. 

Under virology, the annual proficiency content would require respiratory viruses, herpes viruses, enterovirus, and intestinal viruses, as appropriate.

Public comments on the proposed rule suggested that this grouping of microbiology needs to provide further details to labs. Better understanding the required coverage for organism sample types, specimen type, and test methods would assist labs in enrolling in annual proficiency testing programs. There were also questions as to if it is sufficient for labs to report identifications at the species level or if it is necessary to include more specific detail.

Unintended cost consequences

The proposed rule suggests that ten laboratory participants, at a minimum, be required before a program may offer a proficiency testing analyte. Public commenters expressed concern that this recommendation may limit the ability of laboratories to obtain difficult-to-find samples and comparison data. Some suggested this action would ultimately increase the price of proficiency testing by limiting the number of proficiency testing providers able to comply. Another proposal would limit the online submission of proficiency testing data to one submission, or else require a mechanism for tracking changes to electronically reported results. Several public comments explained that this proposal would complicate unduly the submission process. Concerns noted that this requirement would increase costs as proficiency testing providers would need to reconfigure programs and adopt new audit systems. These costs would likely be passed to laboratory customers.

Unintentional operational consequences

According to the Clinical Laboratory Improvement Amendments of 1988, proficiency testing programs must be offered by either a private nonprofit organization or a state government. The proposed rule suggests a change that would require “all functions and activities related to administering the PT program must be performed by a private nonprofit organization or state.” Given that the U.S. Department of Health and Human Services already has authority to “resolve technical, administrative, and scientific problems” that may arise with proficiency testing program operations, the proposed rule appears to overreach. 

As noted in several public comments, “all functions and activities” is a broad reach that may require a wide range of services to convert to nonprofit status. This may include shipping, legal, source samples, information technology services, among others. This has the potential to impact the operations of all proficiency testing providers and their ability to provide services. 

Hemoglobin A1c

The proposed rule recommends a ten percent acceptance limit for hemoglobin A1c test results. Even though acceptance limits are not intended for use by individual laboratories, a number of public comments expressed concern that this limit is too wide. Some believe it would permit the treatment of patients based on inaccurate test results. One commenter noted that the performance criteria of target value +/- ten percent is acceptable for non-commutable material coupled with a +/- six percent acceptable rate for commutable whole blood material.


CMS and the Centers for Disease Control and Prevention have been analyzing analytes and acceptable performance measures well in advance of issuing this proposed rule. While modernization of proficiency testing rules is overdue, the next iteration should reflect current practice and permit enough flexibility to accommodate future clinical laboratory testing innovation. It is not yet known when a final rule will be issued.