The yield of target cells is low.
Target cell content was over-estimated in the leukapheresis product.
During analysis, target cells were incorrectly counted or an error
occurred during counting of leukocytes. Repeat the analysis of
leukapheresis product for starting target cell content.
- Target cells were poorly labeled with the reagent.
• Reagent has expired. Check use-by date. Do not use any reagent
after the use-by date.
• Reagent was not stored properly. Check storage temperature.
Do not use any reagent that has been stored improperly (see
package insert of the reagent).
• Recommended labeling procedure has not been followed. Refer
to sample preparation and separation procedure chapters in the
manual.
- Cells were lost during the preparation steps.
• Cells were removed with the supernatant into Plasma Waste
Bag and Wash Waste Bags due to incomplete sedimentation
or too early resuspension of the cells, e.g., when the bag was
removed from the centrifuge. Compare leukocyte content of the
unlabeled leukapheresis product and the labeled leukapheresis
product. Check centrifugation settings for proper centrifugation.
Determine cell counts from all waste bags.
• Buffer did not contain HSA. Supplement the buffer with HSA to
a final concentration of 0.5 % (w/v), (see section “Preparation of
CliniMACS® PBS/EDTA Buffer”, chapter 4, STEP 1).
• Centrifuge settings were suboptimal. Check centrifugation
settings.
• Centrifuge imbalance or use of brake or asymmetrical loading of
centrifuge.
- Cell viability decreased during preparation. See section “Viability of
the target cell fraction is less than 90% or the color of the supernatant
during the washing steps was red” below.
- Analysis was incorrect.
• Sampling error occured. Check cell suspension for clumped or
settled cells. Confirm that representative samples have been
taken and repeat analysis.
• Staining error occured. Check flow cytometry reagents. Repeat
staining.
• Flow cytometer settings were improper. Check instrument
settings.
37091/04 – ch20 (Issued: 2020-06)
Troubleshooting
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