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Parts, Accessories & Consumables

In addition to a full range of technical support services, ApogeeFlow offers consumables (e.g. ApogeeMix, Cat#1493 calibration beads), optical filter blocks and hardware upgrades. Please send purchase orders and requests for further information to We accept credit card payments.

Quality System

ApogeeFlow operates under a Quality Management System based upon BS EN ISO 13485:2016 Medical Devices.

Calibration of Cytometers

For situations where a precise calibration to SI units is preferred, ApogeeFlow offers cat#1492 "Light Scatter Calibration Module" which implements a patented process based on particle suspensions of precisely known refractive index (ŊD at 25degC in the range 1.36 to 1.42). This practical approach avoids Mie theory approximations and offers scales calibrated to particular refractive indexes, on light scatter histograms. Consult ApogeeFlow for further details.

Calibration to SI Units by Mie Theory Approximation

Attempts to calibrate flow cytometer light scatter signals to SI base units (e.g. nanometres) based on the Mie solution to Maxwell's equations have associated errors:

  • they are based on estimations of the light scatter angle ranges collected by the detector
  • biological particles are not homogeneous spheres (Mie theory assumes homogenous spheres)
  • the refractive index of biological particles varies
  • user error due to the complexity of the process

Calibration to Silica Test Beads, a Better Reference Unit

To eliminate the complexity and errors introduced by Mie Theory conversion of light scatter signals to SI units, flow cytometer light scatter signals may instead be calibrated to silica test bead diameter. Silica test bead diameter is a simple, precise and reliable alternative reference unit accessible to all flow cytometer users. Test beads have well defined characteristics, excellent long term stability and are low cost. The use of silica test bead diameter as a reference unit is more precise (introduces less error) because the relationship between the optical properties of silica test beads and biological particles is more precisely known than the relationship between the optical properties of biological particles and nanometres. The ‘ApogeeMix' product offers this simple, precise calibration solution.

The simplest and most precise practical method to characterise a flow cytometer's light scatter optics is therefore to use test beads of precisely known characteristics as a calibrator to define a scale based on test bead size instead of attempting to convert to SI units.

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