[Histonet] Proficiency Testing for small labs

[johnson, teri]

Hi Gareth,

Good luck on your upcoming inspection.

Regarding Proficiency testing, labs that don't do the usual barrage of special or immunohistochemical stains need to have some sort of alternate plan for PT. Our lab has outlined alternative assessment in our Quality Assurance Program.  It requires that you provide details in how you perform all your quality items for the lab, including the PT (number of samples, method of comparative testing, criteria for successful and unsuccessful results, investigation details, documentation process, etc.)  See the information from www.cap.org<http://www.cap.org> on this:

"Use alternative assessment methods, when necessary. Tests for which PT is not available or that do not require enrollment in a formal PT program must be assessed twice a year to confirm their reliability. Methods of checking accuracy include split sampling with another laboratory, the use of previously assayed specimens, pooled material, use of PT products usually educational in nature, or clinical correlation. Another example of alternative assessment is the CAP's Sample Exchange Registry, which helps facilitate cooperation around genetic testing. It is important to emphasize to everyone that just performing an alternative assessment is insufficient. As the laboratory medical director, your job is to establish evaluation criteria for the alternative assessment. If a result falls outside the established acceptable range, conduct an investigation in the same manner as you would with formal PT."

In short, we have a bank of paraffin blocks that we use specifically for a specific assay's PT (previously qualified with known expression levels). Every 6 months we perform our particular IHC stain using samples that have been blinded to the operator and pathologist. The operator performs a routine run on those samples and submits them to the pathologist for scoring. Those scores are recorded on a specific document and compared against the previous 6 month score. Concordance must be established according to a pre-defined threshold. It passes or fails, and any failure must be investigated, explained, and re-tested if applicable. Do this for each of your IHC assays. Run more than one sample, and when possible do both positives and negatives ; we do either 3 (100% concordance required) or 5 (80% concordance required, but any failure is still investigated).

Best wishes,

Teri Johnson, HT(ASCP)QIHC
Manager, Clinical Trial Testing

T +1 760 516 5954
teri.johnson at navigatebp.com<mailto:teri.johnson at navigatebp.com>

Navigate BioPharma, Inc.
A Novartis Company
1890 Rutherford Rd.
Carlsbad, CA  92008
USA