Obtaining samples from platelet bags for pH/glucose testing by dipstick to detect bacterial contamination

A colleague from London, Ontario reports that they have evaluated a dipstick method to measure pH/ glucose, similar to that provided by the AABB in Association Bulletin #03-12. According to Appendix II, procedure #3 of the Bulletin - Detecting Platelet Bacterial Contamination by Urine Dipstick Technique, one should "express platelet-rich plasma within connected tubing into the platelet bag and allow to refill. Repeat this step". The Canadian reports that in their hands, they have found this method to be cumbersome, if not ineffective, both when done by hand or with "strippers". She would like to know how others are obtaining aliquots for dipstick testing, so that the sample collection and testing can be done quickly, at time of pooling/issue.

ADDENDA Jan. 21, 2004

The following responses have been received.

1. Editor's note: The following links are germane to this discussion:
   • Using pH and glucose dipsticks to screen for contaminated platelets
   • Using pH paper to QC platelets
   • How are blood banks or transfusion services planning to address the new AABB requirement to have methods to limit and detect bacterial contamination in all platelet components?

ADDENDA Jan. 26, 2004

2. Members are referred to item #5 added today to a related earlier discussion. It is reproduced below:
   
   A colleague at a large hospital in Virginia reports that they continue to do glucose testing on apheresis platelets (see previous comment from Sept 7, 2003). In order to collect the specimens to do this testing, they use the tubing "tails" on the apheresis platelets. They gently mix the platelet bag and strip the platelets into the primary bag with the blue clamp on the tubing or with the hand stripper. This gentle mix and strip is repeated 2 additional times and then a 1 1/2 inch segment is heat sealed and cut (with scissors) from the tubing at plastic seal. This segment is then cut (again with scissors) and a drop of the platelet contents is placed in the glucometer to measure the glucose level. They have done approximately 6,000 glucoses on platelets by glucometer and find this procedure easy enough to do. This method could be used to obtain a specimen for dipstick testing also

ADDENDA Feb. 16, 2004

3. A Texan reports that her hospital will be using a hand-held pH meter that only requires 1 drop of plasma and a pH cut-off of 6.5 to screen for possible bacterial contamination of platelets. In addition, their primary effort will be in discouraging the use of random platelets; at this point "randoms" are used only at that facility when specifically ordered for their neonates. They are in the process of convincing their neonatologist to order platelets by "ml's" needed and not by the number of units needed. This way, they can use apheresis aliquots instead of randoms, in which case they will not be doing bacterial detection at the hospital for those products.

ADDENDA Feb. 19, 2004

4. A colleague from the University of Michigan Hospitals & Health Centers - Blood Bank & Transfusion Service (attribution used with permission) has submitted the following excerpt (PDF) from their procedure draft for obtaining platelet samples for pH dipstick testing. She states that they will be using Whatman^® pH Indicator Paper Strips. They will use a Hematype segment cutter to cut the segment from the platelet tail, making the process less cumbersome.
   
   When the platelet tail is too short, or when they want to repeat testing they will be using a device that has a spike on one end with a Y-shaped tubing on it. One arm has a port that can then be spiked for pooling and the other arm has an opening for dispensing a small aliquot of platelets into a tube. Both arms of this device have a clamp. The spike port has a pull-off top and the other arm has a cap.

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