Use of laboratory tests to guide initiation of autologous hematopoietic progenitor cell collection by apheresis: results from the multicenter hematopoietic progenitor cell collection by Apheresis Laboratory Trigger Survey.

Limited literature describes the value of laboratory "triggers" to guide collection of peripheral blood (PB) hematopoietic progenitor cells (HPCs) by apheresis [HPC(A)]. We used a web-based survey to determine which parameters are used to initiate autologous HPC(A) collection in adult and pediatric patients and to identify common practice patterns. Members of the AABB Cellular Therapy Product Collection and Clinical Practices Subsection and the American Society for Apheresis HPC Donor Subcommittee drafted and developed relevant survey questions. A web link to the survey was distributed by electronic newsletter or email. Responses from 67 programs that perform autologous HPC(A) collections, including academic medical centers (n = 46), blood centers (n = 10), community hospitals (n = 5), and a variety of other medical institutions (n = 6), were analyzed. Ninety-three percent (62/67) of programs used a laboratory parameter to initiate HPC(A) collection. In both adult (40/54, 74%) and pediatric (29/38, 76%) patients, the PB CD34+ cell count was the most common parameter used to initiate HPC(A) collection. The median PB CD34+ trigger value was 10/μL for both patient populations. Among centers routinely using the PB CD34+ cell count to initiate apheresis, 51% (22/43) first sent the test before the patient presented for collection. Although more than 90% of centers used a laboratory test to trigger apheresis in cytokine-mobilized (44/48) or chemomobilized patients (50/53), only 57% (30/53) used a laboratory trigger if the patient was mobilized with granulocyte colony-stimulating factor plus plerixafor. Forty-two percent (21/50) of programs that routinely measured the PB CD34+ count before collection and discontinued further HPC(A) collection based on product CD34+ cell yield also stopped if the PB CD34+ value before apheresis was considered too low to proceed. Most programs use the PB CD34+ cell count to trigger autologous HPC(A) collection. Some centers also use this parameter to stop further collections. Laboratory tests are used less frequently to initiate apheresis when patients are mobilized with plerixafor. These data reveal ongoing diversity in clinical practices and suggest that consensus guidelines on use of laboratory parameters may further optimize HPC(A) collection.