The Invitrogen Attune NxT Flow Cytometer uses a unique volumetric sample and sheath fluid delivery system. Samples are introduced into the Attune NxT cytometer with syringes, producing accurate measurements of the volumes of acquired samples, and thus accurate calculation of cell concentrations. Recommendations for optimizing experiments to measure the most accurate concentration are summarized in Table 1.
Table1. Recommended parameters for accurate counting. The values listed are guidelines only. Accuracy and precision of the measurement should be verified per individual protocol.
|0.2–3 μm||>3 μm|
|Example sample type|
|Flow rate||12.5–1,000 μL/min||100–1,000 μL/min|
|Sample concentration||500–106 particles/mL|
|Event rate||<8,000 events/sec|
|Sample volume||50–4,000 μL|
The sample concentration measurement may be affected by sample type, sample volume, sample processing rate, event rate, sample settling, and other factors. It is recommended that a comparison of serial dilutions of a sample be used to verify that the sample concentration measurement is accurate (e.g., twofold dilution = twofold change in concentration). In the event that the sample concentration measurement is not within the desired accuracy, the measured value may be calibrated to a known standard. If conducting a calibration, use the same instrument settings that will be used in the experiment (e.g., sample, sample processing rate, volume analyzed) during the calibration process.
Figure 1. Data demonstrating the measured vs. expected concentration as a function of flow rate. (A) Smaller particles (e.g., 0.2–3 μm) show consistent concentration results across all flow rates for the three concentrations of beads tested. (B) Larger particles (e.g., 10 μm) show consistent results across the flow rate range 100–1,000 μL/min.
For Research Use Only. Not for use in diagnostic procedures.