Megamix-Plus FSC Beads for Cytometer Settings in Microparticle Analysis - Kit for 50 Tests Ref. 7802

Oct 3, 2026

Uploaded by Aria

Megamix-Plus FSC provides a fluorescent bead mixture for cytometer setup and standardized microparticle (MP) counting in the 0.3–1 µm-eq. range. The protocol helps optimize FSC thresholds near the cytometer size sensitivity limit and supports reproducible MP counts. It also enables transferring protocol and scatter settings between cytometers and assessing instrument stability over time. The document details reagent composition, storage, preparation steps, and acquisition settings, with limitations for instruments lacking sufficient FSC resolution.

LanguageEnglish

CategoryHealthcare

FormatPDF

Pages4

Reading Time10 min

AccessFree to download

1 INTRODUCTION

2 PRINCIPLE

3 REAGENT PROVIDED

4 MATERIAL REQUIRED BUT NOT PROVIDED

5 REAGENT PREPARATION AND STORAGE

6 PROCEDURE

6.1 Bead preparation

6.2 Generation of cytometric protocol and instrument settings

Megamix-Plus FSC Beads for cytometer settings in microparticle analysis Kit for 50 Tests Ref. 7802 For Research Use Only. Not for Use in Diagnostic Procedures. 1 INTRODUCTION Biological microparticles ("MP") are cellular vesicles of heterogeneous size ranging from 0.1 to 1 µm. Due to such small size, MP analysis requires working conditions close to the size-related sensitivity limit of the cytometers. Standardization of MP count requires to master this limit for an optimal compromise between MP analysis and background exclusion. This limit has significantly progressed with the advent of the latest generations of instruments from 0.5 down to 0.3 µm-eq.* (ref. 1) . Also, experience with Megamix have shown that FCM instruments may not all behave the same in terms of scatter response to sub-micron particles, some being optimized to use Forward Scatter (FS or FSC), e.g. Beckman-Coulter (BC) Gallios/Navios and others making best use of Side Scatter (SS or SSC) parameter, e.g. Becton-Dickinson FACS and LSRs (ref.2) . Megamix-Plus FSC reagent is most appropriate for use with FSC-optimized cytometers. * µm bead-equivalents, special arbitrary unit used to remind that FCM can not provide absolute measurement of MP size but only reference points to standardize analysis (ref. 1) . 2 PRINCIPLE Megamix-Plus FSC is a mix of fluorescent beads of varied diameters selected to cover the theoretical MP size range (0 .1 to 1 µm) . Beads acquisition according to the following procedure allows setting the cytometer to study MP within a constant size region (0 .3-1 µm-eq.) and getting reproducible MP counts. The intrinsic numerical ratio of 2:1 from the 0.3 µm to 0.5 µm beads helps fine tuning FSC threshold for those instruments which only provide coarse discontinuous adjustment (e.g. BC Gallios). Finally, Megamix-Plus FSC also helps to transfer both the protocol and scatter settings from one cytometer to another and to check the stability over-time. Limitation: flow cytometers using different optical designs for scatter collection may not feature enough FSC resolution to be used for standardized MP counts. This will lead to a bad resolution between 0.3 and 0.5 µm beads (no clear-cut separation in Fig. 3) . Some of them may work better using SSC as the prime size-related threshold parameter. For these instruments, standardized MP analysis may rather be done using Megamix-Plus SSC beads (ref. 7803) that are optimized for the use of SSC. This alternative approach should provide similar MP counts despite using an other parameter and different reference beads (ref.2) . 3 REAGENT PROVIDED 1 vial of 25 mL of beads. Megamix-Plus FSC is a mix of beads with the following diameters: 0.1 µm, 0.3 µm, 0.5 µm and 0.9 µm. 4 MATERIAL REQUIRED BUT NOT PROVIDED • Cytometer, FSC-optimized model (e.g. BC Gallios/Navios) . • Stirring machine type Vortex. • Cytometry tubes (similar to those recommended for MP analysis, i.e. polypropylene tubes, with low dust and protein adsorption) . • Adjustable pipette with disposable tips (500 µL) . 5 REAGENT PREPARATION AND STORAGE Unopened vial remains stable until expiration date printed on the label when stored at 2-8°C. Do not freeze. The reagent is ready for use. Resuspend this reagent by vortexing for 10 seconds before use. Stability after opening: until expiration date printed on the label at 2-8°C when free of contamination. 6 PROCEDURE The reagent must be at room temperature for the procedure. We recommend to run Megamix-Plus FSC beads before each series of MP analysis. 6.1 Bead preparation Label a cytometry tube. Pipette into it 500 µL of Megamix-Plus FSC reagent after shaking vigorously the reagent vial for at least 10 secondes by vortexing. 6.2 Generation of cytometric protocol and instrument settings Refer to the Operator’s Manual of the cytometer for instructions on how to perform cytometric readings. Vortex the tube just prior to analysis. For the acquis

FAQs

What is Megamix-Plus FSC used for in microparticle analysis?

It is used to set up cytometers for standardized MP analysis by optimizing FSC thresholding and enabling reproducible MP counts in the 0.3–1 µm-eq. region.

Which cytometer type is Megamix-Plus FSC most appropriate for?

It is most appropriate for FSC-optimized cytometers, where FSC provides sufficient resolution for the 0.3–0.5 µm bead separation.

How should the reagent be prepared before running the beads?

Keep the reagent at room temperature, then vortex the vial for 10 seconds before use; for the run, transfer 500 µL into a labeled cytometry tube after shaking the vial vigorously.

Oct 3, 2026

Uploaded by Aria