IG/TCR Clonality Status (Accredited)

Programme objective To assess a laboratory’s ability to accurately determine IG and/or TCR clonality status, using molecular methods.

Clinical/scientific background The diagnosis of lymphoid malignancy can be a challenge that requires many different disciplines of pathology. Molecular analysis of clonality is a valuable supplementary tool, as in principle, all cells of a malignancy have a common clonal origin. Among the various markers used for detecting clonality in suspected lymphoproliferative disorders, gene rearrangements of the immunoglobulin (IG) and T-cell receptor (TCR) stand out as the most commonly utilised targets. These IG and TCR rearrangements occur from the earliest stages of B-cell and T-cell development onward. A random combination of one variable (V), diversity (D), and joining (J) gene segment results in the formation of a unique V(D)J exon that encodes the actual antigen-binding region of the IG or TCR chain. Consequently, each lymphocyte possesses a unique antigen receptor molecule on its surface, and the likelihood that two different lymphocytes coincidentally bear identical receptors is negligible. Therefore, identical rearrangements do not originate from multiple independently generated cells but rather reflect the clonal nature of the cell population involved. Assessing whether the genetic rearrangements exhibit a homogeneous or heterogeneous pattern is therefore the fundamental principle behind clonality testing.

Sample type/distribution Two lyophilised cell based (cell line, patient or buffy coat) samples are issued three times per annum. Trial schedule can be found here:   https://www.ukneqasli.co.uk/eqa-pt-programmes/trial-schedules/

Trial duration Standardly trials for this programme are live/open for a minimum of 4 weeks. Please note, trials issued/closing in August or December are extended by 1 week. An automated email is sent 2 days prior to the trial closing, to any participant that has not returned results, warning them of the trial closure date.

Subcontracted areas Pre-issue and post-closure testing of samples for this programme are subcontracted, although the final decision about sample suitability lies with the EQA provider; no other activities in relation to this EQA programme are subcontracted.

Updates to the programme for current or upcoming year Electronic educational traces are planned during the trial year.

To register for this programme, please click here.