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Phone: (719) 264-6250


Assessment of Stem Cell Samples

for Cellular Therapy



There is a lot of hype around stem cells and stem cell therapy. This is particularly the case for the multitude of uses of umbilical cord blood. There are more than 80 diseases for which umbilical cord blood is now being tested or used. In some cases, it is not the stem cell that are called upon to provide a response, but rather the interaction of other cells present in the unit that are responsible. Regardless of whether the important cell entity involved are the stem cells or other cells, little, if any, quality control and/or potency testing is performed with validated assays. As a result, the quality and/or potency of the stem cells used by transplant physicians is rarely, if ever known. That is, no predictive information is obtained to ascertain whether the stem cells used in a patient will perform as expected and lead to a successful outcome. The assays, developed by HemoGenix®, help to provide this information.


For more information, please contact HemoGenix® at or call (719) 264-6250. These services are also available through Science Exchange


The following samples can be used for testing: 

  1. Fresh samples of any volume down to about 0.1mL shipped cold, but not frozen.

  2. Cryopreserved samples of any volume down to about 0.1mL shipped on dry ice or in a liquid nitrogen dewar.

  3. Samples can from umbilical cord blood, bone marrow, normal or mobilized peripheral blood or purified populations, e.g. CD34+, CD133+.

  4. Samples of red blood cell or plasma-reduced are also acceptable. These are usually considered TNC ot total nucleated cell fractions, which may contain upwards of 30% red blood cells. These will be processed to a mononuclear cell (MNC) fraction for assay.

HemoGenix® has developed specific procedures for processing samples about 0.1mL. 

Stem cell "quality" is defined as the ability of stem cells to proliferate.
Stem cell proliferation is measured using a standardized and validated ATP bioluminescence assay called HALO® SPC-QC. This assay measures two primitive stem cell populations that are necessary for short- and long-term engraftment and reconstitution.

There are many applications where stem cell "quality" should be determined: These include, but are not limited to:

  • Ascertaining the efficiency of new equipment and tools to fractionate and/or process stem cells.
  • Optimizing red blood cell or plasma-reduction protocols. 
  • Optimizing a cryopreservation procedure.
  • Assessing the "quality" of cryopreserved cells stored for long periods of time. 
  • Optimizing a thawing procedure.
  • Cell fractionation and separation procedures.

  • Samples can be tested under Good Laboratory Practice (GLP) compliance.
  • All assays incorporate standards and controls and have been validated according to FDA guidelines for bioanalytical method validation.
  • Assay calibration and standardization allows results to be compared between samples over time.
  • The ATP bioluminescence technology used in HALO® SPC-QC as a signal detection readout provides the highest sensitivity available to detect the rarest of stem cell populations.
  • HALO® SPC-QC studies are usually completed in just 5 days.
  • After completion of the assessment, a report will be sent (usually by email) within 2-3 business days.

Please note that stem cell "quality" should not be mistaken as potency or strength. 

Assessing Umbilical Cord Blood Bankability 

  • Only cord blood units demonstrating the highest stem cell "quality" should be permanently stored for clinical use. A rapid, single stem cell assay was developed for this purpose that has the capability of measuring large numbers of cord blood samples with high throughput capability. This assay is called STEMpredict™.
  • STEMpredict™ is a unique, 3-day in vitro assay that determines metabolic viability (cellular function) and whether the stem cells in the unit have the functional ability to proliferate.
  • STEMpredict™ is usally performed on a sample of the fresh umbilical cord blood, but can also be used on cryopreserved samples.
  • STEMpredict™ is capable of triaging low quality from high quality cord blood samples. 
  • HemoGenix® has determined acceptance values above which stem cell growth functionality can be predicted.

Assessing the Optimum Time for Mobilized Peripheral Blood Collection
  • Stem cells are mobilized in patients by consecutive administrations of granulocyte colony-stimulating factor (G-CSF). A patient may or may not "mobilize" or may "mobilize" to a lower degree than expected.
  • STEMpredict™ can help determine whether a patient has "mobilized" and the extent of the mobilization".
  • The same 3-day STEMpredict™ assay used to determine cord blood bankability can be used to rapidly determine whether stem cells have been induced as a result of G-CSF administration or other mobilizing agent and whether those stem cells can be stimulated to grow.

Samples can be tested under Good Laboratory Practice (GLP) compliance.

  • The assay is standardized and validated.
  • Results allow samples to be compared over time.
  • Proprietary Suspension Expansion Culture™ (SEC™) and ATP bioluminescence technology provides the highest assay sensitivity available with the most reliable results.
  • After completion of the study, a results report will be sent (usually by email) within 2-3 business days.
  • STEMpredict™ is a "best practice criteria testing" platform.

The importance of measuring potency of a cellular therapeutic product cannot be underestimated. It is probably one of the most important parameters to measure prior to use, but also one of the most misunderstood. Potency is used to:

  • Ensure consistency during manufacture of the product.
  • Ensure stability of the product.
  • Measuring potency can avoid product failure due to incorrect potency. This is particularly the case for umbilical cord blood, which demonstrates about 20% graft failure that has been attributed to lack of or low potency.
  • Measuring potency also reduce potential toxicity.
  • A potency assay should predict whether the product can be released for use.

All of these reasons indicate that potency is a prospective measurement, not a retrospective measurement.  

  • Stem cell potency contract services are available for umbilical cord blood, mobilized peripheral blood, bone marrow and purified stem cells (e.g. CD34+) from these tissues.
  • Stem cell potency and quality of the tissue sample is measured using HALO®-Potency.
  • HALO®-Potency is an FDA validated assay platform that complies with FDA and EMA guidelines and regulations for potency assays.
  • Hematopoietic stem cell potency contract services are performed under GLP compliance.
  • Hematopoietic stem cell potency of the sample is measured for the lympho-hematopoietic high proliferative potential - stem and progenitor (HPP-SP) cell and the primitive hematopoietic stem cell population (CFC-GEMM) against a reference standard of the same tissue material.
  • HemoGenix® has established reference standards for umbilical cord blood, mobilized peripheral blood and bone marrow mononuclear cells that are used to determine the potency ratio of samples from the same tissues.
  • Stem cell culture is performed using Suspension Expansion Culture™ (SEC™) Technology with an ATP bioluminescence readout, the most advanced and sensitive, non-subjective signal detection system available.
  • Assay requires a minimum of only 120,000 sample cells.
  • Results available usually after 5 days of culture, but may be extended to 7 days for increased sensitivity.
  • Thanks to ATP Bioluminomics™ Technology, results from different samples can be compared over time.
  • All results are included in a Certificate of Potency Analysis (CoPA). The CoPA provides information on the stem cell potency ratio, stem cell “quality” and the release criteria. Final product release determination should be made by the Medical Director or similar authority and only after all information pertaining to the characterization of the product have been reviewed.

Please note that when considering stem cell potency of hematopoietic cellular therapeutic products, total nucleated cell count (TNC), dye exclusion viability and detection of viable CD34+ cells reperesent "minimum testing criteria" and are not potency assays and do not comply with FDA or EMA guidelines or regulations. However, cell count and viability are necessary to use the cells to measure potency. The number of CD34+ cells also provides additional characterization information. The CFU assay is not a potency assay and is not compliant with potency assay regulations. 

After hematopoietic stem cell transplantation, early phase reconstitution is determined by the ability of the patient to produce red blood cells, granulocytes (neutrophils) and platelet that can be detected in the circulation. The time at which these entities are found can vary significantly, but usually occurs within 2-3 weeks after transplantation. Ahead of significant numbers of cells appearing in the circulation, primitive progenitor cells can be detected using HALO®-96 PMT to measure:

  • Erythropoietic progenitor cells (BFU-E),
  • Granulocyte-Macrophage progenitor cells (GM-CFC), and
  • Megakaryopoietic progenitor cells (Mk-CFC).

Unlike the colony-forming unit (CFU) assay which takes between 12 - 14 days to perform, HALO®-96 PMT takes only 5 days and provides predictive information regarding the time to engraftment.

For remission to occur after stem cell transplantation, all cell lineages of both the hematopoietic and lymphopoietic systems must be functioning. The immune system usually reconstitutes later than hematopoiesis. However, the latter must also be shown to be tri-lineage reconstitution. To demonstrate that reconstitution is balanced, HemoGenix® provides three types of "global" reconstitution assays.

Global" Tri-Lineage, 4-Population Hematopoietic Reconstitution

This assay detects:

  • Primitive hematopoietic stem cell population (CFC-GEMM)
  • Erythropoietic progenitor cells (BFU-E),
  • Granulocyte-Macrophage progenitor cells (GM-CFC), and
  • Megakaryopoietic progenitor cells (Mk-CFC).

"Global", 5-Population Hematopoietic Reconstitution

This assay detects:

  • Primitive lympho-hematopoietic stem cell (HPP-SP)
  • Primitive hematopoietic stem cell population (CFC-GEMM)
  • Erythropoietic progenitor cells (BFU-E)
  • Granulocyte-Macrophage progenitor cells (GM-CFC), and
  • Megakaryopoietic progenitor cells (Mk-CFC).

"Global" 7-Population Lympho-Hematopoietic Reconstitution

This assay detects the same 5-populations as above, but also includes the T- and B-lymphocyte lineages.

  • Primitive lympho-hematopoietic stem cell (HPP-SP)
  • Primitive hematopoietic stem cell population (CFC-GEMM)
  • Erythropoietic progenitor cells (BFU-E)
  • Granulocyte-Macrophage progenitor cells (GM-CFC)
  • Megakaryopoietic progenitor cells (Mk-CFC).
  • T-Lymphopoietic progenitor cells (T-CFC)
  • B-Lymphopoietic progenitor cells (B-CFC)

Patient Monitoring during Clinical Trials

To determine the response of patients to drugs and the occurnce of potential toxicity to specific stem and progenitor cell populations during clinical trials, the same "global" HALO®-96 PMT assays can be employed using a small volume of peripheral blood or bone marrow biopsy, if performed.

Advantages of HALO®-96 PMT to Determine Time to Engraftment "Global" Reconstitution or Patient Monitoring during Clinical Trials
  • Like all other HALO® assays, HALO®-96 PMT is always calibrated and standardized prior to sample measurement. This means that the cell response can be compared directly from one sample to another over time.
  • HALO®-96 PMT measures the ability of individual cell populations to proliferate providing the most rapid and predictive information available.
  • Thanks to SEC™ and Bioluminomics™ technology, all assays provide validated, reliable and accurate results, using advanced cell culture and the most sensitive assay readout available.
  • Rapid 5 day assay turnaround time that can be extended to 7 days for increased sensitivity.
  • For patient studies and clinical trial monitoring, in particular, studies can be performed GLP or non-GLP.