The test a laboratory has to pass three times a year

Somebody sends the lab unknown samples on purpose

A laboratory that runs anything more than the simplest tests has to enroll in a proficiency testing program. The program mails it samples. The lab does not know the right answers.

Enrollment is not general. A lab enrolls for each specialty and subspecialty it wants to be certified in, so a certificate does not vouch for work the lab never sat an exam in.

The program has to be approved, and the approval sets the tempo. To be approved for routine chemistry, a program must provide "a minimum of five samples per testing event". There must be "at least three testing events at approximately equal intervals per year."

So the lab behind a hormone panel or a metabolic panel is answering graded unknowns several times a year, every year, for as long as it holds the certificate.

The hardest rule is not the test, it is how the test must be taken

The exam only means something if the lab does not treat it as an exam. The regulation spends most of its length on that.

The governing sentence is short. "The laboratory must test the samples in the same manner as patients' specimens."

That is then made specific. The samples must be examined or tested "with the laboratory's regular patient workload by personnel who routinely perform the testing in the laboratory, using the laboratory's routine methods."

The lab has to test them the same number of times it routinely tests patient samples. It cannot run the unknowns five times and report the average.

And two people sign for it. The individual testing the samples and the laboratory director both attest that the samples were folded into the normal workload by the normal methods.

Talking to another lab about the answers is the cardinal sin

The rule that carries the heaviest penalty is about communication, not competence.

Laboratories "must not engage in any inter-laboratory communications pertaining to the results of proficiency testing sample(s)" until after the reporting deadline for that event has passed.

That reaches inside a single company. A laboratory with multiple testing sites or separate locations cannot discuss the samples across its own sites before the deadline either.

Sending the sample out is worse. A lab must not send proficiency testing samples, or portions of them, to another laboratory for any analysis it is certified to do itself.

A lab found to have referred a sample intentionally "may have its certification revoked for at least 1 year." A lab that receives someone else's proficiency testing sample has to report that it received it.

There is one narrow allowance. It covers a referral limited to reflex, distributive or confirmatory testing that a patient specimen would lawfully have gone out for. Where that is so and it is not a repeat, the referral is treated as improper rather than intentional.

The score, and the number that actually ends a certificate

Grading is arithmetic, and the pass mark is stated. For routine chemistry, failing to attain a score of "at least 80 percent of acceptable responses for each analyte in each testing event" is unsatisfactory performance for that analyte.

Missing the event entirely is not neutral. Failing to participate is unsatisfactory performance and scores zero, with a narrow allowance where patient testing was suspended and the lab told both the program and the inspecting agency.

Being late is treated the same way. Returning results after the program's deadline "results in a score of 0 for the testing event."

One bad event is not the trigger. The trigger is repetition: failing the same analyte in "two consecutive testing events or two out of three consecutive testing events" is unsuccessful performance.

The same two-out-of-three pattern applies to the overall event score, so a lab can lose its standing on general sloppiness as well as on one stubborn analyte.

What happens after a failure is graded, not automatic

A first failure does not have to end in a sanction. For an initial unsuccessful performance the agency may instead direct the lab to train its personnel, obtain technical assistance, or both.

That door closes in three situations the regulation names. Immediate jeopardy to patient health and safety. A failure to show that the problem has been addressed. Or a poor compliance history.

Where the lab is left standing, it still has homework. For any unsatisfactory result the lab must undertake appropriate training and employ the technical assistance needed to correct the problem.

Remedial action has to be documented, and the documentation kept for two years from the date of the event. The underlying records of how each sample was handled are kept for two years as well.

Coming back takes longer than going out

Reinstatement is not a matter of passing the next round.

A lab that lost certification for a specialty must demonstrate sustained satisfactory performance on "two consecutive proficiency testing events, one of which may be on site," before reinstatement is even considered.

And there is a floor on the clock. The suspension or limitation runs "not less than six months" from the date it started.

That combination matters for a reader trying to time things. Two consecutive events at roughly four-month spacing plus a six-month floor means a lab out of a specialty is out of it for the better part of a year.

The tests nobody offers an exam for

Proficiency testing programs do not cover everything a laboratory can run. Newer assays and unusual ones often have no approved program at all.

The rules do not let those tests go unchecked, but they do check them differently.

Where a test is not covered by an approved program, or where compatible samples are not offered, the laboratory has to verify its own accuracy. The frequency is stated in the rule's own opening words: "At least twice annually, the laboratory must verify the accuracy".

The same self-verification applies where a score exists but does not reflect real performance, such as an event the program could not grade.

That is worth knowing before reading a result. A specialized assay may be sitting on the lab's own twice-yearly accuracy check rather than on an external graded exam, and the report will not say which.

Any of this is askable, and what it does not settle

The results are not sealed inside the program. Programs must furnish the agency with cumulative reports on each laboratory's performance, for the purpose of building a system that makes results available "upon request of any person."

Programs keep their records of laboratory performance for five years, or longer where legal proceedings need them.

Two limits belong on this. Proficiency testing measures whether a lab can hit a target on a mailed sample. It says nothing about whether the right test was ordered, whether your specimen was drawn and stored properly, or whether the number was interpreted sensibly.

It also says nothing about the seller who arranged the draw. A panel ordered through a telehealth intake is run by a laboratory that stands or falls on its own certificate, and the two are separate businesses with separate records.

Only subpart H of part 493, its program criteria in subpart I, and the evaluation standard at section 493.1236 were read for this article. The certificate types, the personnel rules and the sanctions each sit in their own subparts and are covered separately on this site.

Sources

Each document below is named as it names itself, with the date printed on that document rather than the day it was read.

1. Title 42 Code of Federal Regulations section 493.801, Condition: Enrollment and testing of samples, read in full for the enrollment rule, the same-manner requirement, the inter-laboratory communication ban and the referral penalty — Electronic Code of Federal Regulations, Office of the Federal Register, July 2022
2. Title 42 Code of Federal Regulations section 493.803, Condition: Successful participation, read for the training-instead-of-sanction path and its three exceptions — Electronic Code of Federal Regulations, Office of the Federal Register, January 2003
3. Title 42 Code of Federal Regulations section 493.807, Condition: Reinstatement of laboratories performing nonwaived testing, read for the two-event requirement and the six-month floor — Electronic Code of Federal Regulations, Office of the Federal Register, April 1995
4. Title 42 Code of Federal Regulations section 493.841, Standard; Routine chemistry, read for the eighty percent pass mark, the zero for nonparticipation and late return, and the two-out-of-three rule — Electronic Code of Federal Regulations, Office of the Federal Register, February 1992
5. Title 42 Code of Federal Regulations section 493.931, Routine chemistry, read for program content and frequency of challenge — Electronic Code of Federal Regulations, Office of the Federal Register, July 2022
6. Title 42 Code of Federal Regulations section 493.903, Administrative responsibilities, read for the cumulative reporting duty and the five-year record retention — Electronic Code of Federal Regulations, Office of the Federal Register, July 2022
7. Title 42 Code of Federal Regulations section 493.1236, Standard: Evaluation of proficiency testing performance, read for the twice-yearly self-verification requirement — Electronic Code of Federal Regulations, Office of the Federal Register, January 2003