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Blood controls for flow cytometry


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Blood Controls

1. Can I lyse the red blood cells within the CD4 Blood Controls using my normal method?

Our current QC procedure follows a stain, lyse, no wash method using 'Quicklysis' a gentle lysing solution from Cytognos. However, CD4 Blood Controls are also compatible with FACS lyse.

2. Can I use CD4 Blood Controls in the same way as a whole blood sample?

Yes, treat the CD4 Blood Controls in the same way as a normal whole blood sample.

3. Which antibodies are compatible with CD4 Blood Controls?

This link provides details of the antibody conjugates that have been validated by Cytomark for use with CD4 Blood Controls.

N.B. We recommend that all antibody conjugates are validated for your own purpose prior to use.

4. Can CD4 Blood Controls be used on a haematology analyser?

Cytomark CD4 Blood Controls have been used successfully on the following haematology analysers:

  • ABX Pentra 120
  • ABX Pentra 80
  • ABX Pentra DX 120
  • Beckman Coulter UniCel DxH 800
  • Cell-Dyn Ruby
  • Cell-Dyn Sapphire
  • Cell-Dyn 3500
  • Coulter LH750
  • Siemens ADVIA 2120i
  • Siemens ADVIA 2120
  • Siemens ADVIA 120
  • Sysmex XE2100
  • Sysmex XT1800i
  • Sysmex XE2100D
  • Alere PIMA

N.B. Please validate CD4 Blood Controls for use on your own machine prior to use. These controls are designed for use on a flow cytometer.

5. Should I be worried if the forward scatter and side scatter profiles diminish with time?

No, as long as the absolute cell counts and percentages are within the range given in the associated Quality Control Certificate of Analysis.

6. What is the shelf life of CD4 Blood Controls?

Open vial stability of CD4 Blood Controls is 1 month from manufacture. Closed vial stability is 3 months. CD4 Blood Controls should be stored at 2-8°C (working temperature of CD4 Blood Controls is 18-25°C).

7. How quickly can I receive CD4 Blood Controls following manufacture?

We can send you a schedule of CD4 Blood Controls manufacture. If you wish to be added to this alert then please email

8. Can the CD4 Normal Blood Control be used in other applications than for CD4+ cell assessment?

Yes, CD4 Normal Blood Controls contain stabilised white blood cells within a normal range specified on the associated Certificate of Analysis. Therefore, they can be potentially used in applications other than for CD4 monitoring.

N.B. Please validate the CD4 Normal Blood Controls for your own study prior to use. Please contact for sample requests.

9. What procedure is used in your QC testing?

We use a stain, lyse, no wash procedure, whereby very little cell manipulation is conducted. This method will also minimise cell loss and ensure that cell absolute counts and percentages are within range.

10. The cell absolute counts that I am observing on the flow cytometer for Cytomark Blood Controls are not within the expected ranges given on the Certificate of Analysis (COA). What does this mean? Has the product failed?

The product has not necessarily failed if cell counts are observed outside the expected ranges.

If the staining and enumeration method that was used by the operator is not the same as the one used by Caltag Medsystems to QC the product i.e. Stain/enumeration (using BD Multitest IMK kit, and Trucount tubes), lyse (BD FACS Lyse), no-wash and flow cytometric testing on the BD FACS Calibur, then values outside of the ranges specified on the COA are not uncommon. This is because there are inherent differences if alternate antibody conjugated fluorochromes are used, especially if the clones are different, and if the enumeration method is different e.g. lyophilised beads versus liquid counting beads.

The ranges given on the COA are a guide to the customer and the important point in terms of product performance is that consistent cell absolute counts are observed over time.

Furthermore, we have observed absolute cell count differences when other methods and cytometers are used. Sample preparation was performed using the Lymphogram CYT-C001 and CD45 OC515, Cytognos antibody cocktail, BC Flow Count Beads and the lyse (BC Versalyse), no wash method. Acquisition and analysis were performed on a BC Navios flow cytometer. The derived results show lower absolute counts for our CD4 low and normal blood controls when compared to equivalent certificates of analysis using our current QC process. This comparison can be seen below:

CD4 Normal Blood Controls

CD4 Low Blood Controls

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