Reproducibility studies for experimental epitope detection in macrophages (EDIM)
Dennis Japink1, Marius Nap2, Meindert N Sosef3
1Department of General Surgery, Atrium Medical Center Parkstad, Henri Dunantstraat 5, 6419 PC Heerlen, The Netherlands; Department of General Surgery, Maastricht University Medical Center, P. Debyelaan 25, 6229 HX Maastricht, The Netherlands; GROW-School for Oncology and Developmental Biology, Maastricht University Medical Center, P. Debyelaan 25, 6229 HX Maastricht, The Netherlands.
Introduction:
We have recently described epitope detection in macrophages (EDIM) by flow cytometry. This is a promising tool for the diagnosis and follow-up of malignancies. However, biological and technical validation is warranted before clinical applicability can be explored.
Methods:
The pre-analytic and analytic phases were investigated. Five different aspects were assessed: blood sample stability, intra-individual variability in healthy persons, intra-assay variation, inter-assay variation and assay transferability. The post-analytic phase was already partly standardized and described in an earlier study.
Results:
The outcomes in the pre-analytic phase showed that samples are stable for 24h after venipuncture. Biological variation over time was similar to that of serum tumor marker assays; each patient has a baseline value. Intra-assay variation showed good reproducibility, while inter-assay variation showed reproducibility similar to that of to established serum tumor marker assays. Furthermore, the assay showed excellent transferability between analyzers.
Conclusion:
Under optimal analytic conditions the EDIM method is technically stable, reproducible and transferable. Biological variation over time needs further assessment in future work.
