Information on the Ring Trial Molecular Cytogenetics


The Ring Trial Molecular Cytogenetics aims at assuring the quality of laboratories offering the technique of metaphase FISH (= fluorescence in situ hybridization). Based on images of FISH results available online or on samples delivered to the participants, the Ring Trial wants participants to find an (optional) aberration and that they issue a correct report based on their findings.

Performance interval

Once per year.


This trial is split up in two different exercises, called “Case 1” and “Case 2”.
In general, for Case 1 between 10 and 25 images of FISH results are made available online, together with the corresponding clinical case description and including the result of GTG banding, the indication for FISH analysis and the information on the applied probes.
As an alternative, every three to five years participants will receive cell suspension (dropped on slides) of a clinical case which has to be handled and analysed according to the participant’s own standard operation procedures. Under normal conditions of transport (by ordinary mail) the shipped samples are supposed to be stable for 14 days.
In addition, in Case 2 participants have to solve a theoretical problem dealing with the appropriate application of the rules of ISCN nomenclature.


Based either on the available images or on the received sample, which is to be handled according to the participant’s own SOP, participants in this trial are supposed to hand in a report of findings (a letter). This report is uploaded after login on Additionally, participants have to answer questions or give additional information in an online questionnaire.


Participants are expected to find the (optional) aberration and to write a correct report of findings.
Furthermore, they are supposed to formulate the correct karyotype and to answer properly the questions of Case 2.
Altogether, the precondition for successful participation is a ratio of 60% of the attainable amount of points. The detailed list of criteria is sent out together with each trial.


Participants will obtain a certificate by BVDH e. V. after successful participation (valid for two years). So far, metaphase-FISH is not yet subject to the German guidelines for medical diagnostics (RiLiBÄK).

Ring trial management

PD Dr. Thomas Liehr
Institut für Humangenetik
Am Klinikum 1
07747 Jena
Tel. 036419396850
Fax 036419396852

Dr. rer. nat. Anja Weise
Institut für Humangenetik
Postfach 10 05 61
07705 Jena
Tel. +49 3641 9 39 68 30