Return to CAP Home
Printable Version

  Feature Story

title
 

cap today

Language barrier falls with checklist change

Divide and conquer

March 2003
Karen Southwick

After several years of work, the CAP has finalized changes to its Laboratory Accreditation Program checklist questions that clarify what participants must do to meet calibration verification requirements.

The changes are designed to eliminate confusing language and probably will not require most labs to alter their procedures.

"The changes were necessary because in older versions of the checklist and in CLIA, the terminologies of calibration, calibration verification, and reportable range were being used interchangeably," says Greg Miller, PhD, professor of pathology at Virginia Commonwealth University Health System, Richmond, and a consultant to the CAP Chemistry Resource Committee.

Mixing the terms for two different processes created inconsistencies and confusion that the Chemistry Resource Committee, aided by the Instrumentation and Therapeutic Drug Monitoring/ Endocrinology committees, sought to clear up in the new checklist version.

The two-year effort was spearheaded by Dr. Miller and Edward R. Ashwood, MD, immediate past chair of the Chemistry Resource Committee and
chief medical officer and laboratory director at ARUP Laboratories, Salt Lake City.

Ever since the CLIA regulations took effect, the language on calibration verification has been vague, Dr. Ashwood says. "Our committee spent hundreds of hours discussing this and we finally decided to put our own language to it"—namely, "some very practical questions to put on the checklist that we felt were scientifically valid."

Separating terms

The changes focus on separating calibration verification and analytical measurement range (AMR) validation. First, "you need to calibrate your instruments at least every six months or as frequently as the manufacturer recommends," says Dr. Ashwood. In lieu of calibration, "you can do something to prove that calibration hasn’t changed, which is calibration verification"—that is, assaying suitable material with target values specific for the method and determining that the correct analyte value is recovered. Calibration verification or recalibration is also required if the laboratory has altered its method, such as changing critical reagents or replacing a critical instrument component.

Second, laboratories must validate the AMR by demonstrating that "your measurement value is always linear between the highest and the lowest values," Dr. Ashwood says. Calibration itself can be a form of AMR validation if there are at least three calibrators that span the AMR. However, the manufacturer’s requirements for calibration of many assays use only one or two calibrators, which correctly set method calibration over the AMR. Yet a two-point calibration assumes linear recovery of analyte over the full AMR. In that case, the linear recovery must be verified separately using materials that span the full AMR. The CAP checklist requires validation of three points for AMR: the lowest value, midpoint, and highest value (or values as close to those points as possible).

"We [in the committee] prefer at least five," says Dr. Ashwood,
"but CLIA says three," so the checklist question specifies three. "Once every six months you’ve got to validate your analytical measurement range: Take a low sample and a high sample, mix them together, and produce three points."

So most laboratories must perform two procedures to meet the new checklist requirements: Calibrate or verify calibration at least every six months and perform AMR validation at the same interval. If the calibration or calibration verification includes three or more analyte levels which cover the AMR, the latter is not required.

Dr. Ashwood notes that under the old checklist, many inspectors "felt that if you were calibrating every six months that was enough, so they weren’t requiring AMR validation." The new checklist language details more precisely when AMR must be done.

"The majority of labs will still need to do AMR," Dr. Miller says, because "most of the commercially available methods do not use calibrators that cover from the very low to the very high values." Calibration verification and AMR apply to quantitative procedures, including chemistry, toxicology, and immunology.

A third term defined in the checklist is the clinically reportable range (CRR)—the analyte values that a method can report as a quantitative result, allowing for specimen dilution or concentration. It is thus an extension of the AMR. If labs decide to report values outside the AMR, they must have a defined protocol that, for example, specifies the dilution agent and stipulates, when applicable, which CRR values are meaningful as numeric results and when to report less-than or greater-than information.

At first, Dr. Ashwood says, the CRR checklist question the committee designed was not clear enough. "We wanted lab directors to define the upper limit of the CRR [on each assay]," he says, "but we decided that was impractical because there are some assays, such as a tumor marker, you might dilute until a numeric value is obtained." The new checklist question simply makes sure that if laboratories are diluting specimens, they have a protocol to follow.

"This protocol might specify the upper limit, and it might not," says Dr. Ashwood. "With some assays you can’t do dilutions because they measure ratios. With other assays you may want to set some upper limits based on practical clinical considerations." For each procedure, "there should be language on how to handle specimens with values outside of the AMR."

Says Dr. Miller, "If you choose to report results higher or lower than the AMR, you need to have a defined dilution protocol." Laboratories that don’t have such protocols should develop them before their next CAP inspection.

Most laboratories, however, are probably already doing what the checklist changes require. "This shouldn’t have a major effect on laboratory procedures," Dr. Miller says. "We haven’t really changed what labs must do. We’re just clarifying two separate analytical validation procedures."

Nonetheless, laboratories in the CAP Laboratory Accreditation Program are tremendously interested in the checklist changes. More than 1,600 people participated in two teleconferences on the changes hosted by Drs. Ashwood and Miller in November.

How checklists evolve

The CAP inspection checklists evolve continually under the direction of the resource committees, says Ronald Lepoff, MD, chair of the Commission on Laboratory Accreditation and vice chair of pathology at the University of Colorado Health Sciences Center, Denver.

The recent changes are important because they end confusion that has existed for years. "I’ve traveled as far as Singapore for lab meetings and had people ask me, ’What does this mean?’" he says, referring to the old calibration verification language.

He praises Drs. Miller and Ashwood and the committee members for their work. "We’ve been trying for several years to come up with wording that makes sense. I think they’ve gotten there."

After the resource committees—which are responsible for content and practice—recommend changes for the checklist, the recommendations must be approved by the commission and ultimately by the LAP checklist commissioner, now Stephen J. Sarewitz, MD, staff pathologist at Valley Medical Center, Renton, Wash.

The commissioner’s job is to integrate input from the resource committees and feedback from members, staff, and accredited laboratories "into appropriate changes to the checklist," Dr. Sarewitz says. "We also try to keep the changes practical for our inspectors in the field."

The checklist changes must also be sent for review to the Centers for Medicare and Medicaid Services. If the CMS does not object within 30 days, the updated checklist is posted on the CAP Web site and included in packets of information sent to labs before their inspections.

The most recent changes will take effect with the next round of laboratory inspections, Dr. Lepoff says. The accreditation packet and disk sent to laboratories contain the checklist version for which they’ll be responsible.

In the future, Dr. Sarewitz hopes to schedule regular new editions of the checklist so laboratory professionals know when to expect them. "Previously, checklists did not come out on a scheduled basis," he says. This year, he plans checklist editions for release at the end of this month (incorporating the changes detailed here), the end of July, and the end of November. After that, "we will go to two editions a year," he says.

In addition, to help laboratories identify changes, "we’re instituting a flagging system in which new and revised questions will be identified," Dr. Sarewitz says. Also planned for the future are customized checklists consisting of questions that apply to particular laboratories. For example, if you’re doing anatomic pathology and excluding electron microscopy, your laboratory’s customized checklists won’t contain electron microscopy-related questions.

For more information on the new chemistry checklist and related issues, visit the CAP Web site. Dr. Miller will make presentations on the changes during the June 21-25 CLMA/ ASCP meeting and during the July 20-24 AACC meeting. The checklist workshop at the CLMA/ASCP meeting will take place June 25; the workshop at the AACC meeting is scheduled for July 22.

Karen Southwick is a writer in San Francisco.