BD Vacutainer® CPT™ Cell Preparation Tube with Sodium Citrate

Limitations

Volume of Blood

The exact quantity of blood drawn will vary with the altitude, ambient temperature, barometric pressure, and venous pressure. The minimum volume of whole blood that can be processed without significantly affecting the recovery of mononuclear cells is approximately 3.0 mL for 4 mL draw and approximately 6 mL for 8 mL draw. However, hematological parameters such as a low hematocrit or a low mean corpuscular hemoglobin concentration(7) may also adversely affect product performance, with increased red blood cell maintained above gel barrier.

Temperature

Since the principle of separation depends on a gel movement, and the viscosity of the gel varies with temperature, the temperature of the system should be controlled between 18-25° C during centrifugation.

Centrifugation

Since the principle of separation depends on the movement of formed elements in the blood through the separation medium, the RCF should be controlled at 1500 RCF to 1800 RCF. The time of centrifugation should be a minimum of 20 minutes. (As noted in the troubleshooting section, some specimens may require up to 30 minutes for optimal separation.) Centrifugation of the BD Vacutainer® CPT™ Tube up to 30 minutes has the effect of reducing red blood cell contamination of the mononuclear cell fraction. Centrifugation beyond 30 minutes has little additional effect. If separation is incomplete and the mononuclear cell "band" (or layer) is not disturbed, the BD Vacutainer® CPT™ Tube may be recentrifuged.

Time

Blood samples should be centrifuged within two hours of collection. Red blood cell contamination of the separated mononuclear cell fraction increases with increasing delay before centrifugation. Mononuclear cell recovery decreases with increased time delay before centrifugation, falling to approximately 40% mononuclear cell recovery at 24 hours.

Cell Separation

As with other separation media, density gradient separation using BD Vacutainer® CPT™ Tubes may alter the proportion of some lymphocyte subsets (e.g., T and B cells) from those in unseparated whole blood(4,5). This alteration is believed to be relatively insignificant in normal cases. However, in cases where the subject is leucopenic or lymphopenic, the selective loss of one subset may alter proportions significantly.

Certain disease states and/or drugs may also alter cell density, and therefore, affect separation using BD Vacutainer® CPT™ Tubes(6).

Microbial Contamination

Microbial contamination of reagents may alter the results obtained on cells separated using BD Vacutainer® CPT™ Tubes.

Separated Cell Assays

For determinations other than those described in the results section, the user should establish that the values obtained meet the necessary criteria for his or her application.

Platelet Contamination

Studies(7) indicate that mononuclear cell samples separated by the BD Vacutainer® CPT™ Tube method have approximately 1.3 times the platelet concentration obtained using the FICOLL™ HYPAQUE™ method.

FICOLL is a trademark of Amersham Biosciences AB
HYPAQUE is a trademark of Amersham Health AS