StemExpress provides peripheral blood Leukopaks® and Mobilized Leukopaks® from healthy IRB consented donors that are tested negative for HBV, HCV, and HIV. Donor samples are collected using the Spectra Optia® Apheresis System, where cell-rich mononuclear cells are extracted using a continuous flow method directly into a collection bag containing the anticoagulant ACD-A. Apheresis products are sent out fresh to customers or sent for further sorting at the StemExpress laboratory.
At StemExpress’ state-of-the-art laboratory, each source material can be processed to allow for the isolation of a variety of immune cells and their subsets, as well as hematopoietic stem cells. Each primary cell isolate comes with a Certificate of Analysis that guarantees viability, purity, and cell count.
Your Cells, Your Way!
LEUKOPAKS®
- 1 bag/1x1010 TNCs
- ≥90% viability
- Enriched MNCs
- Low hematocrit
- Low granulocytes
- Two-week turnaround
- Variety of collection sizes
MOBILIZED LEUKOPAKS®
- 1 bag/2x1010 TNCs
- ≥90% viability
- Enriched CD34+ cells
- Low hematocrit
- Low granulocytes
- Two to four-week turnaround
- 1st or 2nd-day collections
HIGH-QUALITY LEUKOPAKS

CONFIDENCE IN YOUR RESEARCH
StemExpress facilities comply with strict guidelines regarding the production, processing, and management of tissue-based cellular products to ensure exceptional quality.
- Compliant with FDA CFR 1271 regulations
- current Good Manufacturing Practices/Good Tissue Practices (cGMP/cGTP)
- Enterprise Resources Planning software (ERP) and Quality Management System (QMS)
- Collection protocols are approved by the company’s Medical Director and Independent Review Board (IRB) in accordance with federal law
DONOR SELECTION
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- Extensive donor pool
- Recallable and repeat donors
- Specific donor demographics (age, weight, ethnicity, etc.)
- Donor lifestyle characteristics (BMI, smoker/non-smoker, etc.)
- Medical history (allergies, medications, etc.)
- HLA, RhD, and ABO typing available
- Additional infectious disease screening (CMV, etc.)
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CELL COLLECTION/PROCESSING
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- Special processing procedures available
- Variety of volumes available
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FLEXIBLE SHIPPING OPTIONS
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- Customizable packaging options
- FedEx®, World Courier®, UPS®
- Same day delivery in select cities
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Frequently Asked Questions
Yes, a donor is eligible to donate white blood cells every 4 weeks.
Usually around 8x109 PBMCs.
Yes, certain locations can receive same day courier delivery. We can also provide same day air shipments.