Language barrier falls with checklist change
Divide and conquer
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.
are designed to eliminate confusing language and probably will not
require most labs to alter their procedures.
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
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.
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
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.
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.
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.
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,
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
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.
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
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.
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.
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.
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.
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."
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.
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.