The purity of target cells is low.
- Non-target cells were retained.
• Mobilization of target cells was poor. Very low number of target
cells has occurred. Therefore, a low number of contaminating
non-target cells (e.g. granulocytes, monocytes, platelets) may
lead to decreased purity.
• Insufficient plasma or immunoglobulins were present during
magnetic labeling. Follow the instructions given for the magnetic
labeling (see chapter 4, STEP 1).
If a final concentration of about 30% autologous plasma in
the sample during magnetic labeling cannot be guaranteed,
add immunoglobulin to the sample. A final concentration of
1.5 mg/mL is recommended for the efficient blocking of non-
specific reagent binding during magnetic labeling.
Unexpected events
– DEPLETION 2.1 and
DEPLETION 3.1
The depletion e
ffi
ciency is low.
If the depletion e
ffi
ciency is insu
ffi
cient, process the remaining sample
with a new tubing set and su
ffi
cient new bu
ff
er. A new labeling of the
cells to be depleted should be considered. Determine the cell count and
percentage of cells to be depleted and enter actual sample parameters
during set-up of the instrument (STEP 2). If visible clumps occur, it may
be helpful to filter the cells prior to a new run. Take into account that cells
may be lost due to clumping and additional filtration.
- Capacity of reagent and/or tubing set was exceeded. Refer to capacity
limit of the relevant application.
- Incorrect determination of cells to be labeled by the reagent.
- Incorrect sample parameter input. Cross-check parameter input with
analysis results.
- Reduced viability of the cells. Dead cells can bind non-specifically
to separation column thereby reducing the labeling capacity of the
column, potentially resulting in lower depletion efficiency. Ensure
better leukapheresis product quality and process product as fresh as
possible. Stored products that are older than 24 hours should not be
used. If storage is necessary, leukapheresis product should be kept
at controlled room temperature (+19 °C to +25 °C [+66 °F to +77 °F]).
The cell concentration should not exceed 0.2
×
10
9
/mL. If necessary,
dilute the leukapheresis product with autologous plasma to achieve
optimal cell concentration.
37091/04 – ch20 (Issued: 2020-06)
Troubleshooting
5 – 13
