Monitoring frequent platelet pheresis donors for developing thrombocytopenia

A Compliance Officer at a transfusion service in Massachusetts wonders how other centers monitor frequent platelet pheresis donors for developing thrombocytopenia. According to the compliance officer, she has heard that a center uses an average of the last three (if available) pre counts, and NOT a platelet count from the current or immediately preceding donation. She wonders if this practice is compliant with current AABB Standard 5.5.3.7 Plateletpheresis Donors which reads "If plateletpheresis is performed more frequently than every 4 weeks, a platelet count shall be obtained and shall be greater than 150,000/microLiter before subsequent plateletpheresis procedures are performed." In addition, this practice might be compliant with proposed AABB Standard 5.5.3.5.2 which becomes effective May 2002 and which reads "The results of platelet counts performed before or after a procedure may be used to qualify the donor for the next procedure." However, the inquiring compliance officer reports having recently heard that an institution received a citation from FDA for the above mentioned practice of using a rolling average of serial platelet counts. Do other centers have a similar approach, and if so, what is the timing of that platelet count(s) in relationship to the platelet pheresis donation? If you use a rolling average of serial platelet counts, has that practice come under criticism by any regulatory or accreditation granting organization?

The following replies were submitted in response to the above:

1. A blood banker in Texas reports that his center follows the memorandum from the FDA of October 7, 1988 for determining plateletpheresis donor eligibility. To donate platelets, a donor must meet one of the following 3 criteria:
   • They have not donated platelets in the last 8 weeks
   • If they have donated platelets in the last 8 weeks, they have a post-count from the last procedure that is greater than 150,000/ul, or
   • If they have donated platelets in the last 8 weeks and their last post count is 150,000 or less, they have a precount done before being put on the machine that is 151,000 or greater. The responding blood banker has automated hematology analyzers at all of their 14 fixed platelet donation sites so samples can be drawn and tested while the donor waits. For those donors needing a precount before qualifying to donate, they may do a "hand" stick with a butterfly needle so that they don't use one of the antecubital veins needed for a two arm procedure. For donors already qualified on the basis of a previous post count, or who qualify because they have not donated platelets for the last eight weeks, they draw an EDTA tube and run a CBC once the donor is on the machine to tweak the settings for the baseline platelet count and maximize the collection efficiency. For their mobile platelet collections where a automated hematology analyzer is not available, they can only draw donors who qualify on #1 or #2 above. All of this answers the question of how to qualify donors, but the Texas blood banker is not sure that is the same thing as monitoring donors for the development of thrombocytopenia. It is challenging to come up with a procedure for systematic medical review of regular platelet donors in a center that draws 50 to 60 plateletpheresis donors a day. The Texan would be interested in knowing how other centers do that.
   
   
2. A blood banker from Minnesota was a member of a few committees that developed platelet donor monitoring/qualifying recommendations more than 25 years ago that were later adopted by FDA. According to the Minnesota blood banker the intent was specifically to allow the use of a post donation count from the previous donation as a matter of convenience so the donor wouldn't have to wait for results of a predonation count to determine if he/she was eligible. There never was any intent that this could involve pooling results of several previous counts, as this is just a way to overcome the potential low value from the immediate previous donation. In the opinion of the Minnesotan, IF the count was too low from the previous donation, the count should be repeated prior to the new donation or the donor should be deferred. It's as simple as that.
   
   
3. A California blood banker reports that she thinks there needs to be a distinction made between the use of the serial average for QUALIFYING the donor, versus using that same information to program the equipment for efficient collection. Most of the plateletpheresis equipment available are very efficient at removing platelets - their efficiency is based on internal calculations based on such parameters as today's platelet count and size of the donor. If you QUALIFY a donor based on the POST platelet count from the last donation, you know only that the count was above 150,000 (the FDA's cutoff). Beyond qualification, you need to know what the count is today. If you have a platelet counter available, you draw a sample and program the platelet equipment based on today's draw. However, if you have a remote site or mobile without platelet counting abilities, the California blood banker has found that a reasonable estimate of today's platelet count (on a donor already qualified based on their last POST count) can be made by averaging the last 3 PRE-counts. (Her center draws platelet donors no more often than every 2 weeks, and try to use pre-counts that are less than 6 months old for the averaging). So, they do both a PRE count and a POST count on each donor. In the centers with counting equipment, they use today's pre-count for setting the machine, and today's post count for determining whether the donor can keep their appointment in 2 weeks. In the centers/mobiles where there are not counting equipment, they use the last 3 visit PRE counts for setting the machine (today's PRE will be averaged for the next collection), and today's' post count to qualify for the next donation. If the post count is not >150,000, they do have donors come between donations for another sample and they use that sample for qualification purposes. They monitor their donors based on all the information available. The departments flag any donor with low PRE or POST counts - and the charts are reviewed with all the history every 4-6 months for dropping PRE counts.
   
   
4. A blood banker in Northern California reported that at her facility they use the pre count from the donation immediately proceeding the current donation to qualify the donor. They use the average of the last 3 pre counts as the platelet count entered into the machine.

ADDENDA March 6, 2002

5. Another blood banker reported that they use the post count from the previous donation to "qualify" the frequent donor (must be greater than 150,000) They also use an average of 3 previous pre-counts to enter necessary data into the instrument to set yield, etc.... but NEVER to qualify the donor.
   
   
6. A blood center in a state bordering the Pacific Ocean reports that they currently use the platelet count from the previous donation to qualify a platelet donor. However, in the past they have used an average of the last three platelet counts to enter into the apheresis machine without incident or discussion from the FDA. They believe that using the average of the last three platelet counts is a way to get a more accurate number to enter into the apheresis machine. However, the reporting institution did not find the rolling average platelet count to be any more accurate or predictable than just using the previous donation count. Even when they averaged the platelet count to enter into the apheresis machine they still actually qualified the donor based on the previous count. If the donor's previous platelet count was less than 150,000, they would not collect the platelet but would draw a platelet count to verify the low count. They would not average a <150,000 count with another higher count and accept the donor.

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