ACCREDITATION STATUS:

Extension of scope pending.

CLINICAL APPLICATION:

Prenatal Genetic Diagnosis testing for rearrangements by array or NGS.

PURPOSE OF PROGRAMME:

To establish the cytogenomic analytical and interpretative capabilities of the participating laboratory specific to rearrangement testing of Blastomere/Trophectoderm samples.

ANALYTES:

PROGRAMME OF ANALYSIS:

DNA samples are sent to the laboratory, each with a referral card to mimic a routine diagnostic case.  Instructions and a user guide are available on the website. The scheme is not prescriptive as to the technique used (e.g. array, NGS) provided the limitations of the test used are stated in the report (ISO15189). Any abnormal case will have a rearrangement ≥10Mb (loss or gain). Laboratories are expected to quantify any gain or loss (i.e. 1, 2, 3 or 4 copies). The participant analyses the sample, interprets the results and reports via the CEQAS website. The EQA is open for 6 weeks. Results can be entered at any time during this period. Any non-submitting labs will be contacted and given 24 hours to submit a late result.

DATA ANALYSIS:

All EQA cases are validated prior to release.  Results are assessed by a panel of experts against set marking criteria based upon professional guidelines. There are three marking categories, Analytical, Interpretation and Clerical Accuracy. Each category carries two points. Deductions are made in accordance with the severity of the omission.  A “critical error” is an error made in either the analytical or interpretive category that could lead to serious clinical consequences or imply a significant lack of diagnostic skill or scientific knowledge on the part of the participating laboratory. All critical errors are given a zero score and are designated as poor performance.  A critical error in one category may result in the remaining categories being left unmarked. Any poor performance is ratified by the PGD Specialist Advisory Group.

PERFORMANCE SCORING:

Satisfactory/Poor. A non-submission is also given a poor performance.

PERFORMANCE MONITORING:

Yes.

PERSISTENT POOR PERFORMANCE:

This is defined as: a) Two poor performances in any PGD array/NGS EQA in which the laboratory participates, over three or more distributions of material, within a 36 month rolling period; b) A poor performance within one year following a previous persistent poor performance designation.