Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2024 Mar 7;55(2):220-226.
doi: 10.1093/labmed/lmad062.

The identification of diurnal variations on circulating immune cells by finger prick blood sampling in small sample sizes: a pilot study

Dayna Bushell  1 , Jonathan Kah Huat Tan  2 , Jessica Smith  2 , Christian Moro  1
Affiliations

The identification of diurnal variations on circulating immune cells by finger prick blood sampling in small sample sizes: a pilot study

Dayna Bushell et al. Lab Med. .

Abstract

Objective: There are well-described impacts of biological rhythms on human physiology. With the increasing push for routine blood tests for preventative medical care and clinical and physiological research, optimizing effectiveness is paramount. This study aimed to determine whether it is feasible to assess diurnal variations of peripheral lymphocyte prevalence using finger prick blood in a small sample size.

Methods: Using polychromatic flow cytometry, the prevalence of lymphocytes was assessed using 25 µL fingertip blood samples at 8 AM and 5 PM from 8 participants.

Results: TH cells and B cells showed significantly higher percentages in the 5 PM samples, whereas NK cells demonstrated a significantly higher morning percentage. T cells, leukocytes, and cytotoxic T cells showed no significant changes.

Conclusion: The detection of diurnal variations demonstrates that small blood volumes can be used to detect lymphocyte variations. The lower blood volume required provides a new testing method for clinical and research settings.

Keywords: T cells; blood; clinical; lymphocytes; physiology; variations.

PubMed Disclaimer

Conflict of interest statement

The authors have nothing to disclose.

Figures

Figure 1.
Figure 1.
Gating method for samples. A, Lymphocytes are first selected based on forward scatter area (FSC-A) and side scatter area (SSC-A) parameters. B, Peridinin chlorophyll protein-cyanine5.5 (PerCp-Cy5.5) vs FSC-A dot plot showing gating for live cells following lymphocyte gating. Singlet gating is performed using FSC-weight (W) vs FSC-height (H) dot plots (C) and SSC-W vs SSC-H dot plots (D). E-J, Cell staining examples using fluorescein isothiocyanate (FITC) and phycoerythrin (PE) conjugated antibodies for one participant following lymphocyte, live cell, and singlet gating.
Figure 2.
Figure 2.
Individual values and mean ± SEM (line) for morning (9 AM) and afternoon (5 PM) blood samples (A, C, E, F: n = 8; B, D: n = 7). ns, not-significant, *P < .05, ** P < .005.
See this image and copyright information in PMC

References

    1. Dunlap JC, Loros JJ, DeCoursey PJ.. Chronobiology: Biological Timekeeping. Sinauer Associates; 2004.
    1. Refinetti R. Circadian Physiology. 3rd ed. CRC Press; 2016.
    1. Cui S, Chen Y, Guo Y, Chen D.. Clock genes and gastric cancer. Biol Rhythm Res. 2022;53(11):1720–1734. 10.1080/09291016.2021.2020993 - DOI
    1. Tsujino N, Sakurai T.. Circadian rhythm of leptin, orexin and ghrelin. Jpn J Clin Med. 2012;70(7):1121-1125. - PubMed
    1. Sato T, Ida T, Kojima M.. Role of biological rhythms in the performance of physical activity. J Sports Med Phys Fitness. 2017;6(3):125-134. 10.7600/jpfsm.6.125 - DOI