"Cell therapy products derived from adipose tissue have some unique processing issues with regard to obtaining accurate cell counts. This is because processing methods may not only show us the nucleated stromal vascular fraction (SVF) cells but also the micellular and microvesicle particles. This is true for both veterinary and human clinical products, and poses special concerns for in-clinic processing where the cell therapy dose is correlated with cell numbers and other QC data is not especially useful.

In this study, multiple cell counting methods were compared for SVF cell reparation that were derived from canine adipose tissue using commercially-available rocessing kits. The data clearly showed that many non-nucleated particles appear cell-like by size and shape, and can lead to counting errors with automated counters. In addition, certain reagents important to processing can have properties wherein the reagents alone (e.g., lecithin) may be counted as cells. The most accurate cell numbers were from hemocytometer-counting of cells stained with 4´,6-diamidino-2-phenylindole (DAPI) which shows the nuclei in concert with a viability stain such as trypan blue. The data clearly showed that care must be taken when counting cells used as a therapeutic dose."

This is an important issue particularly as it pertains to autologous cell-based treatments produced by point-of-care devices and/or kits.  I encourage you to read the paper.   

Morrison DG, Hunt DA, Garza I, Johnson RA, Moyer MP*. Counting and Processing Methods Impact Accuracy of Adipose Stem Cell Doses. BioProcess J, 2012; 11(4): 4-17.

* Dr. Moyer is CEO and Chief Science Officer for INCELL Corporation, 12734 Cimarron Path, San Antonio, Texas 78249 USA. http://www.incell.com