Quantitative Analysis of Cell Chimerism

Since 2005 the Department of Cell Chimerism has been organizing an annual proficiency testing program for the quantitative analysis of cell chimerism.

Each participating laboratory has a choice of two variants — basic and extended. The basic variant includes 7 DNA samples, and the extended variant includes 12 DNA samples: recipient, donor, and 5 (or 10) post-transplant samples for quantification.

Aims of EPT:

The quantitative examination of chimerism status - 5 post-transplant samples in the basic variant (10 post-transplant samples in the extended variant) based on the chosen DNA polymorphisms including interpretation (recipient/donor ratio).

The results are compared with the expected values and statistically analyzed by using Z-score.

Categories of results:

• Excellent ([z] ≤ 1) – correct result
• Good (1 ˂ [z] ≤ 2) – correct result
• Acceptable (2 ˂ [z] ≤ 3) – correct result
• Critical ([z] > 3) – incorrect result
• Under the detection limit of the laboratory (the sensitivity of the participant's method is not able to detect the minor genotype – the example: the expected value of minor genotype is 0.2% and the participant with the sensitivity of 1% determines the detection of only the majority genotype - this result is considered to be correct. However if the participant detects both genotypes and quantifies them, the result is evaluated by Z-score.

To achieve acceptable performance of the EPT, at least an 80% success rate is required (that is 8/10 samples in the extended variant, 4/5 samples in the basic variant).

Guarantor: Mgr. Lucie Stefflová (Lucie.Stefflova@uhkt.cz)

• Application form EPT CHIM 2025