The Medical Director of a transfusion medicine service/hospital donor collection program in Missouri reports that their donor program was cited during a recent inspection for not tracking correctly the red blood cell loss of apheresis donors. Unfortunately, the inspector did NOT have any suggestions for how to do this tracking correctly. In fact, according to the Missouri physician, the inspector actually acknowledged that her own lab was not tracking the red blood cell loss of apheresis donors correctly! For this reason the Missouri physician wonders "How do other blood collection centers track red cell loss for apheresis donors and maintain a rolling 12 month log? What equation do centers use for calculating red blood loss for each procedure? Do centers use a different equation according the apheresis machine used, even if each machine has the same model number?

The following comments have been received.

1. Dr. Mark Brecher, Chief of Transfusion Medicine and Professor at the University of North Carolina at Chapel Hill (attribution used with permission) reports that red cell loss is frequently calculated for platelet apheresis donations as the sum of the red cell loss in the sample tubes for typing and disease marker testing (an average hematocrit can be used to approximate this loss) plus the red cells that are left in the tubing sets. The approximate volume of this residual in the tubing sets is available from each apheresis manufacturer by machine type. Dr. Brecher adds that it is also important to note that this residual is a higher amount (also available from the manufacturer) if the red cells cannot be rinsed back to the donor at the completion of the procedure. For example, when his center uses the Gambro Trima for blood component collections, they estimate red cell loss to be 40 mL for a routine platelet collection and 95 mLs if they cannot rinse back to their donor.

ADDENDA Dec. 27, 2005

2. A Collection Director of a community blood center in Bakersfield, California reports that they her center has devised a tracking form on which they record the amount of red cells lost from a donor during pheresis collection procedures. They add up the losses according to information provided in the operator's manuals of the pheresis kits that they use, plus the estimated red cell losses for specimen collected for donor testing, and plus the estimated volume of red cells in any blood components that were donated. She comments that they estimate high and assume that half of any specimen for donor testing is about 50% red cells, so that five 6 mL specimen tubes contains about 15 mLs of red cells. For each unit of pheresis RBCs collected they add 200 mL to the donor's total red cell losses. They track the total red cell losses using a rolling calendar, looking back for 12 months prior to each procedure. They count each whole blood donation on the rolling calendar as 250 mLs, if any were made. When a donor shows up for a donation, they estimate what the red cell loss is likely to be and add that volume to the rolling calendar total. If the current donation will make the donor's red cell losses exceed 1541 mL for the previous 12 months, the donor is not eligible.

She reports arriving at the figure of 1541 mL for annual total red cell losses according to the following calculations:

• Maximum intravascular volume deficit at any time during the procedure: 10.5 mL/kg donor weight
• Minimum qualification weight of donor: 50 kg
• Maximum blood volume donation for smallest weight donor: 50 kg x 10.5 mL/kg = 525mL
• Minimum qualification hematocrit of donor: 38%
• Maximum RBC volume loss/donation @ 38% hematocrit: 525 mL x 0.38 = 200 mL RBC
• Maximum annual donation frequency: 52 wks / 8 wk intervals = 6.5 donations / year
• Maximum whole blood volume loss/ successful apheresis donation: 525 mL + 31 mL for samples + 68 mL for kit residual = 624 mL
• Maximum allowable annual whole blood collected: 6.5 / year x 624 mL = 4056 mL
• Maximum allowable RBC loss volume @ 38% hematocrit: 4056 mL WB x 0.38 = 1541 mL RBC

ADDENDA Dec. 28, 2005

3. According to Linda S. Laukaitis, RN, Manager, Procedure Development (attribution used with permission), United Blood Services (UBS) uses the following method/practice at its centers for tracking the red cell loss of repeat apheresis donors

• RBC/Plasma loss is calculated on a rolling 12-month calendar.
• Maximum allowable RBC loss for all procedures (e.g., whole blood collection, hemapheresis procedures, laboratory samples) collected for the past 12 months is 1540 mL.
• If donor loses 200 mL or more RBCs during a single plateletpheresis procedure, donor is deferred for eight weeks.
• Cumulative RBC loss for the last eight weeks should be less than 200 mL, however, donor is acceptable if subsequent donations is on an instrument with extracorporeal RBC volume (ECV) of less than 100 mL.
• Loss is recorded and calculated using a manual tracking form. The UBS centers also have a database in which the actual loss is entered and a calculation is performed to verify the manual calculations performed by the staff. This verification process must be complete prior to the next donation and is documented on the manual form.

4. A transfusion medicine physician in Stockton, California reports that based on his experience working in donor centers, a cumulative red cell loss of apheresis donors can be tracked on a yearly basis using either a rolling 12 months or a traditional calendar year. In either case, he has found that the simplest approach to estimate the average red cell loss for a procedure is to ask the apheresis kit manufacturer for this information, and then add that amount to the volume taken for test samples. Alternatively, a direct measurement of the blood left in the apheresis kit can be measured, e.g., by weighing several used kits and subtracting the tare weight; then, convert the weight to volume of blood, using the specific gravity of blood for a non-anemic person, for a typical blood donor. Assuming a hematocrit of 40%, one can calculate the volume of red cells. Assuming no unexpected additional blood loss with a procedure, one can record the calculated or measured volume of red cells lost with the procedure and add to the prior total. When the maximum allowed for the year is reached, the donor must be deferred until the next year or 12 month period begins. The Stockton colleague adds that while each type of apheresis machine will likely have a different amount of blood left in its kit, and that volume may vary for each type of procedure, e.g., a plasmapheresis, plateletpheresis, or leukapheresis, the volumes should be consistent for machines from the same manufacturer.

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Ira A. Shulman, MD
CBBS e-Network Forum Editor & Moderator