Soon to be required: current susceptibility testing breakpoints

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“It expects labs to go through a process and find every organism, every method they use and every result they issue, and ask why they’re calling it susceptible or what basis underlies their ability to say it’s resistant,” Dr. Rauch says. That is, how are the determinations made? Sounds simple, she says, because “everybody should know that for every laboratory test”—if the result is positive, for example, what makes it a positive result.

“But in this case, if you’re using automated instruments, people may have been doing this for years and maybe weren’t even working in the lab when it was set up,” and don’t necessarily have the information on hand. In talking with others in recent years about this problem and the need to determine if breakpoints are current, she knows many labs have had “‘aha’ moments” about an outdated breakpoint. Laboratories have been contacting their manufacturers to find out “what breakpoints are hidden in that big black box.”

The CAP, CLSI, CDC, American Society for Microbiology, and Association of Public Health Laboratories created a seven-part breakpoint implementation toolkit, which became available recently, to help labs update MIC breakpoints (https://clsi.org/bit-toolkit). “Luckily, 11385 has had a fair amount of support from partner organizations,” Dr. Rauch says of the collaboration and the resources that are online.

MIC.11385 doesn’t require that every drug that exists be tested using the current breakpoints because each lab chooses which drugs its institution or clients need. “If you have something that is out of date because it won’t detect current resistance in the world of microbes, you can choose to not report that erroneous result. You can test it by another method in your laboratory, such as a manual method,” she says, noting that much of this issue is related to the large, automated commercially available instruments. “Or you could send it to another laboratory.”

She advises working with clinicians and other antimicrobial stewardship partners to determine which drugs are the priorities. “There might be some drugs you don’t report for a while or send out.” The requirement’s phase one status means if the laboratory receives a citation because it hasn’t completed all of this work, “it can respond with the status of its plans,” she says.

Of the activity the new requirement catalyzed in 2021, Dr. Rauch says: “There’s work for manufacturers, work for professional organizations, and work for the labs. This work must be done, however.

“Patient safety is at risk here.”

MIC.22050 Culture Media and Incubation Conditions is a new requirement in the checklist edition released in August.

It requires laboratories to use defined media and incubation conditions to allow for the recovery of potential pathogens for each culture type, specimen, and/or body site. It consolidates and replaces prior microbiology checklist requirements and says at minimum, media and incubation conditions must allow for isolation and identification of potential pathogens for the following: respiratory specimens (Streptococcus pneumoniae and Haemophilus species), urine specimens (Gram-positive and -negative bacteria), genital specimens for Neisseria gonorrhoeae (selective media designed for its recovery, such as Thayer-Martin), and cerebrospinal and other sterile fluids (fastidious bacteria such as N. meningitidis, S. pneumoniae, and H. influenzae).

MIC.11350 Morphologic Observation Evaluation requires the lab to evaluate, at least annually, the consistency of morphologic observation among personnel who perform microscopic analysis from direct specimens and cultured organisms. The requirement now applies to all microscopic analysis, not just stains, and quantitation if applicable.

“The previous version of the checklist requirement focused on stains but now applies to anything you’re looking at under the microscope, including wet preparations. We want all of the staff doing it the same way,” Dr. Rauch explains, adding that the aim is consistency of result reporting.

MIC.16605 Mass Spectrometer Controls requires the laboratory to test appropriate control organisms on each day of patient testing. The revision specifies that the same protein extraction method used for clinical testing must be used when testing the microorganisms for quality control assessment.

“If it’s going to serve as a control, you have to do exactly what you would do for a patient,” Dr. Rauch says. For laboratory-developed tests, the choice and use of control organisms is at the lab director’s discretion. “But they have to make sure that whatever they are doing for controls matches what they are doing for patient specimens,” she says. “That’s the bottom line.”

New and revised requirements in other checklists were reported in the August issue (https://bit.ly/CT-082023) and in the September issue (https://bit.ly/CT-0923-visco).

CAP-accredited labs can access compliance-related resources on www.cap.org (in e-Lab Solutions Suite, log-in required, under Accreditation Resources), including the Oct. 18 Focus on Compliance webinar and other past Focus on Compliance webinars, as well as lab inspection preparation videos. Also online are answers to the most common checklist-related questions, a self- and post-inspection toolbox, and customizable templates and forms for, among other things, competency assessment and quality management.n

Valerie Neff Newitt is a writer in Audubon, Pa.