Introduction
Assays for cell counting using flow cytometry and calibrated fluorescent particles are rapid and accurate. The
single platform method that enumerates T-cells by counting the identifier cells in either a precise known cell
volume or an internal ‘spike’ of a known number of calibrated fluorescent particles by flow cytometry is simple
and efficient (1). These assays allow the counting of T-cells during anti-T-cell globulin treatment of cardiac, lung,
and renal transplant patients (2). In addition, laboratories can determine the absolute count of CD4 and CD8 Tcells
to estimate HIV disease progression with the single platform method (3). Calibrated fluorescent particles and
flow cytometry are also used to count platelets in a wide range of murine models of platelet disorders (4). It is also
possible to count other various cell types with flow cytometry and calibrated fluorescent particles.
Select the link below to download the complete SpheroTECHNICAL NOTE. (PDF format) 
SpheroTechnical Note #15 will provide the following information:
A description of using Spherotech AccuCount beads and flow cytometry for the ratio-metric method of absolute counting
A protocol for using the Spherotech AccuCount beads for cell enumeration
Calculation necessary for using absolution counting beads for cell enumeration
References using the AccuCount beads
Polystyrene
