Unveiling the biological variation of lymphocyte subset counts: Insights from a full-spectrum flow cytometer and the BD MultitestTM 6-Color TBNK kit

Abstract

Background and aims

To estimate the biological variation (BV) for lymphocyte subset counts in healthy adults based on full-spectrum flow cytometry (FS-FCM) and the most commonly used BD Multitest^TM 6-Color TBNK kit in China.

Materials and methods

The study was designed according to the BV Data Critical Appraisal Checklist (BIVAC). Peripheral blood samples were collected from 60 healthy adults every two weeks for a period of 20 weeks (10 samples from each subject). Lymphocyte subsets were quantified using FS-FCM and the kit mentioned above. Bayesian models were used to analyze within-subject BV (CV_I) and between-subject BV (CV_G). Accordingly, the analytical performance specifications (APS) and more were derived. Additionally, the allowable total error (TEa) derived from the BV data in this study was compared with that based on state-of-the-art (SOTA).

Results

The CV_Is for the percentages of CD3⁺, CD3⁺CD4⁺, CD3⁺CD8⁺, CD3^-CD19⁺, and CD3^-CD16/CD56⁺ cells were 3.60 %, 7.05 %, 4.19 %, 10.73 %, and 19.17 %, respectively. The CV_Is for the absolute counts were 13.99 %, 13.51 %, 16.19 %, 16.30 %, and 28.64 %, respectively. The CV_Gs for the percentages were 11.78 %, 21.33 %, 35.20 %, 33.69 %, and 44.36 %, and those for the absolute counts were 30.27 %, 28.84 %, 43.11 %, 46.69 %, and 49.21 %, respectively. No significant differences were observed in the CV_I and CV_G of males and females. The maximum allowable imprecision parameter based on the BV model was absolute CD3^-CD16/56⁺ cell counts (14.3 %). For most lymphocyte subset parameters, TEa based on SOTA in China was less than the optimal TEa obtained from the BV data of this study.

Conclusions

To the best of our knowledge, this study is the first to estimate the BV of lymphocyte subset counts based on FS-FCM and the clinically commonly used BD Multitest^TM 6-Color TBNK kit.