Preserving Blood for Cytometry:
CytoChex, Transfix, and TokuKit Compared

When collecting clinical samples for cytometry, the method you choose to preserve blood samples matters. In this study, we show how commonly used approaches—CytoChex, Transfix, and TokuKit—affect immune cell frequencies and data quality.

Here's a sneak peek at some of our findings:

B cells

CytoChex preserved only 2–3% B cells, representing a 2–5 fold loss compared to the normal range in healthy donors.

T cells

CytoChex showed a 20% frequency of double-positive CD4⁺CD8⁺ T cells, a 2–4 fold increase over the typical frequency.

T-bet

Transfix failed to detect T-bet⁺ cells, preserving <1% compared to the expected ~30% frequency.

Download the results here

Experimental Design

Head-to-head evaluation of common blood preservation methods.

Sample Collection + Storage Conditions

Whole blood was collected from four healthy donors and preserved with three common blood preservation methods: CytoChex, Transfix and TokuKit.
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TokuKit samples were stored at 4 °C or –80 °C for 7 or 14 days, while CytoChex and Transfix samples were stored at room temperature or 4 °C for 1, 2, 3, or 7 days.

Timeline

After storage, samples were analyzed at multiple timepoints depending on the method:

CytoChex: 1, 2, 3, and 7 days
Transfix: 1, 2, 3, and 7 days
TokuKit: 7 and 14 days

Red Blood Cell Lysis

Samples preserved with CytoChex and Transfix were processed using either ACK or BD lysis prior to staining. Since TokuKit contains its own lysis buffer, no additional ACK or BD lysis step was required.

Panel Design

A 44-marker mass cytometry panel was applied to assess T, B, NK, myeloid, and other key immune cell populations

T cells

B cells

NK cells

Monocytes

Dendritic cells (DCs)

Neutrophils

Instrument

Cytometry analysis was performed on a CyTOF® Helios.

The reference range for B cells in healthy donors, when expressed as percent of non-granulocytes, is 5-10%. When evaluating B cell population frequencies:

Cytochex resolved a frequency of ~2-3% across sample conditions.
Transfix resolved a frequency of ~9-11% across sample conditions.
TokuKit resolved a frequency of ~7-9% across sample conditions.

CytoChex

Transfix

TokuKit

The increase in CD4+CD8+ T cells suggests that CytoChex introduces artifacts after storing for greater than 7 days. When double-positive T cells were evaluated, as a percent of T cells:

CytoChex saw a frequency of about 30%.
Transfix saw a frequency of about 1%.
TokuKit saw a frequency of about 3%.

CytoChex

Transfix

TokuKit

Based on Human Protein Atlas data, T-bet expression is expected in NK cells, γδ T cells, and subsets of memory T cells, corresponding to a fraction of both CD3+ and CD3- cells.³ However, in Transfix-preserved samples, a clearly defined T-bet+ population was not observed.

CytoChex

Transfix

TokuKit

Why does sample preservation matter for your team?

Degradation distorts patient immune profiles

When preservation methods degrade or introduce artifacts, immune profiles shift, creating results that reflect preservation instability rather than a patient's true biology.

Failed samples waste time and budget

Degraded samples often fail QC, requiring costly redraws, repeat shipments, and delays in data delivery.

Inconsistencies undermine PD insights

Differences in how long samples sit before processing introduce noise, making it harder to detect real pharmacodynamic signals, mechanism of action, or biomarkers of response.

References

^{1 Miltenyi Biotec.}^{MACS® handbook: Human cells and organs — Human cell sources: Blood (human)}^{[Internet]. [cited 2025 Mar 3]. Available from:}^{https://www.miltenyibiotec.com/US-en/support/macs-handbook/human-cells-and-organs/human-cell-sources/blood-human.html}²^{González-Mancera MS, Bolaños NI, Salamanca M, Orjuela GA, Rodríguez AN, González JM. Percentages of CD4⁺CD8⁺ double-positive T lymphocytes in the peripheral blood of adults from a blood bank in Bogotá, Colombia.}^{Turk J Haematol}^{. 2020;37(1):36-41. doi:10.4274/tjh.galenos.2019.2019.0256}³^{Huang C, Bi J. Expression regulation and function of T-Bet in NK cells.}^{Front Immunol}^{. 2021;12:761920. doi:10.3389/fimmu.2021.761920}

Preserving Blood for Cytometry:
CytoChex, Transfix, and TokuKit Compared

When collecting clinical samples for cytometry, the method you choose to preserve blood samples matters. In this study, we show how commonly used approaches—CytoChex, Transfix, and TokuKit—affect immune cell frequencies and data quality.

Here's a sneak peek at some of our findings: