PGD Blastomere (FISH)|
Accredited UKAS 7872.
Prenatal Genetic Diagnosis - FISH analysis.
PURPOSE OF PROGRAMME:
To establish the cytogenetic analytical and interpretative capabilities of the participating laboratory specific to the testing of Blastomere samples.
|Case Scenario (Part 1)||Qualitative detection of absence/presence of abnormality.|
|FISH Images (Part 2)||Qualitative detection of absence/presence of abnormality.|
MATERIAL PROVIDED: Case scenario and Online images of G-banded metaphases plus other tests as applicable.
DISTRIBUTIONS PER YEAR: 1 (2 parts)
SAMPLES PER DISTRIBUTION: 2
FREQUENCY OF DISTRIBUTION: 1 distribution in accordance with the annual EQA timetable
PROGRAMME OF ANALYSIS:
The EQA consists of two parts: Part 1 involves a work-up for two cases given the clinical information and the referral information on the genetic abnormality; For part 1 all laboratories are expected to explain their probe strategy. Part 2 involves the online analysis of the blastomeres from IVF embryos of these patients. Participants report their findings for part 1 and 2 online. Both parts are open for four weeks each with a short break between the closing of part 1 and the availability of the part 2 images. Results for the relevant part 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.
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.
Satisfactory/Poor. A non-submission is also given a poor performance.
PERSISTENT POOR PERFORMANCE:
This is defined as:
- a) Two poor performances in any PGD Blastomere FISH 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.
The External Quality Assessment Scheme for Molecular Genetics was founded in 1991. In 1999 the Service became known as the UK National External Quality Assessment Service for Molecular Genetics. UK NEQAS for Molecular Genetics is part of NHS Lothian.