The Flow CAST® is intended for the determination of basophil activation in patient whole blood samples by flow cytometry. Our unique marker combination – CCR3 and CD63 – combines the simple gating properties for basophil detection by CCR3 with the solid application of the proven activation marker CD63 in one. Thanks to its easy protocol and smart marker combination the first results can be obtained within one hour – perfect conditions for routine laboratories.

CCR3 as Basophil Marker

Basophils constitutively express the eotaxin receptor CCR3 allowing for a robust and accurate selection of cells. CCR3 is detected with a PE-fluorescence labelled monoclonal antibody. This gating of basophil cells is significantly easier than with any other commercially available BAT.

CD63 as Activation Marker

Upon allergen contact, sensitized basophils degranulate and express the cell surface marker CD63.  It  is detected by a FITC-fluorescence labeled monoclonal antibody. CD63 is currently the best-validated basophil activation marker directly linked to basophil degranulation.


The first control, anti-FcEpsilonRI, is a highly specific monoclonal antibody binding to IgE receptor. The second control, a tripetide (fMLP) activates the basophils by a non-immunological way.

CD203c as Activation Marker 

The CD203c is an other basophil activation marker for allergy detection after CD63. Our CD203c Reagent Set (RUO) is intended for the use within an extended protocol for the Flow CAST® kit, allowing the measurement of both activation markers, CD63 and CD203c, with two different fluorescence labelled antibodies.

Flow CAST® Product Information 

Method Flow Cytometry
Time to Result 1 h (approx.)
Sample Type 50 µl EDTA blood
Marker CCR3-PE / CD63-FITC
Order Code FK-CCR (100 test)
Patents US 8,563,258 B2; EP 2 037 269 B1
CE (IVDR compliant)

Flow CAST®+ CD203C REAGENT SET Product Information 

Method                                    Flow Cytometry
Time to Result 1 h (approx.)
Sample Type                            50 µl EDTA blood
Marker CCR3-PE / CD63-FITC / CD203c-PE-DY647
Order Code FK-CCR + B-CCR-203SET (each 100 test)
Research Use Only



Main applications for the Flow CAST®

The Flow CAST® is an in vitro diagnostic test for the qualitative assessment of basophil activation upon stimulation with specific allergens. It is intended as an aid to diagnosis of immediate type allergic disorders in conjunction with other clinical and laboratory findings.