A unit that has just been collected sits in quarantine until its record is complete. A collected unit becomes suitable for routine transfusion only after its identity, test results, processing history, storage conditions, and final product specifications are reconciled. Each step leaves a traceable record. A component remains in quarantine until every required release criterion is satisfied or an authorized emergency-release procedure documents the exception.
Unit release and traceability
Donor-unit testing
Federal requirements and current FDA recommendations define the infectious-disease tests used for donations in the United States. The exact test combination depends on the donor, collection site, product, and any approved exception. The routine allogeneic release set includes the following markers.1-3
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| Agent or condition | Laboratory marker used for routine release |
|---|---|
| Hepatitis B virus | Hepatitis B surface antigen, antibody to hepatitis B core antigen, and hepatitis B virus nucleic acid testing |
| Hepatitis C virus | Antibody to hepatitis C virus and hepatitis C virus nucleic acid testing |
| Human immunodeficiency virus | Antibody to human immunodeficiency virus types 1 and 2 and human immunodeficiency virus type 1 nucleic acid testing |
| Human T-lymphotropic virus | Antibody to human T-lymphotropic virus types I and II |
| West Nile virus | Nucleic acid testing under the current seasonal and geographic testing strategy |
| Syphilis | A serologic test required for each donation |
| Trypanosoma cruzi | Antibody testing at least once for an allogeneic donor, with repeat testing controlled by the current policy |
| Babesia species | Licensed nucleic acid testing for donations collected in FDA-designated jurisdictions; approved pathogen reduction may cover eligible platelet and plasma components under FDA guidance |
A repeatedly reactive screening result, an unresolved result, or a donor-eligibility problem keeps the donation from routine release. The unit and every component prepared from it remain linked and quarantined while the facility applies its confirmatory, notification, lookback, reentry, and disposition procedures. A lookback identifies the donor's prior donations and applies the required quarantine, notification, and disposition steps. Donor-history assessment remains part of release because the laboratory tests have agent-specific detection windows.
When a delay would threaten a patient's life, federal rules permit release before required testing is complete through a physician-authorized emergency procedure. The container must state "FOR EMERGENCY USE ONLY BY" followed by the recipient's name, identify completed and incomplete tests, and retain the applicable warning statements. Testing continues promptly, and the receiving facility is notified at once if a later result changes product suitability.1
The laboratory also tests the donor's red cells for ABO and D. Plasma or serum from each allogeneic donor is tested for unexpected red-cell antibodies. A clinically significant antibody affects component labeling and the use of plasma-containing products.2,3
ABO and D confirmation
Donor ABO testing includes forward grouping with anti-A and anti-B and reverse grouping with A1 and B reagent red cells. The two parts must agree before the unit receives a final ABO label. A discrepancy remains unresolved until testing and records support one interpretation.
Test D directly first. Test a donor unit that is nonreactive by the initial method with the required weak-D method. A positive result in either phase means the donor unit is labeled D-positive. This donor-labeling rule differs from clinical decisions about an individual patient with a weak or variant D result.1,3
Labels and identification
The final label identifies the product and links it to the donation record. It includes the proper name and product code, donation identifier, ABO and D type when applicable, anticoagulant or additive solution, approximate volume when required, donor classification, expiration date and time, storage conditions, and applicable attributes or warnings. The donation identifier, product code, facility identifier, and ABO and D information are machine-readable on a component intended for transfusion. Processing records connect the final label with donor testing, component preparation, modifications, inspection, and disposition.1,3
ISBT 128 provides the internationally recognized coding structure used by most US blood establishments. Its Donation Identification Number contains 13 characters:
- a 5-character facility identification number;
- a 2-character collection-year code; and
- a 6-digit sequence number.
Flag characters and the printed check character occupy separate positions beside the 13-character Donation Identification Number. The assigned number is globally unique for 100 years. The original number remains visible through later handling, while product codes and division identifiers distinguish the components prepared from that collection.4
Preservation and storage
Anticoagulants and additive solutions
The collection solution prevents clotting and supports cellular metabolism. Citrate binds ionized calcium. Phosphate provides buffering and supports red-cell metabolism. Dextrose supplies substrate for glycolysis, and adenine supports adenosine triphosphate production. Additive solutions replace much of the removed plasma and may include mannitol or other membrane-stabilizing ingredients.
The final dating period comes from the licensed collection system and its instructions. These common systems illustrate the relationship between solution and red-cell dating.3
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| Solution | Principal use and maximum dating in the licensed system |
|---|---|
| Acid-citrate-dextrose solution A | Common in apheresis; 21-day dating when used in a licensed whole-blood or red-cell system |
| Citrate-phosphate-dextrose | Whole blood or red cells, 21 days |
| Citrate-phosphate-double dextrose | Whole blood or red cells, 21 days |
| Citrate-phosphate-dextrose-adenine | Whole blood or red cells, 35 days |
| Additive solutions AS-1, AS-3, AS-5, and AS-7 | Red cells, 42 days when prepared in the corresponding licensed system |
Temperature and transport
Temperature limits protect cell function and slow microbial or chemical deterioration. Continuous monitoring, alarms, calibrated devices, and documented responses protect stored inventory. A validated shipping container must maintain the applicable transport condition for its expected route and duration.3,5
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| Product | Storage control | Dating or handling point |
|---|---|---|
| Whole blood and liquid red cells | 1–6 °C; routine transport at 1–10 °C | Expiration follows the anticoagulant, additive, and processing system |
| Whole blood intended for platelet preparation | Controlled toward 20–24 °C until separation | Processing time and temperature follow the validated platelet method |
| Whole-blood-derived platelets | 20–24 °C with continuous gentle agitation | A single component has 5-day dating; an eligible closed prestorage pool may have product-specific dating |
| Apheresis platelets | 20–24 °C with continuous gentle agitation | Dating may extend from 5 through 7 days with the approved container and bacterial-risk control strategy |
| Cold-stored apheresis platelets | 1–6 °C without agitation; routine transport at 1–10 °C | An approved alternative procedure may allow dating through 14 days for actively bleeding patients when conventional platelets are unavailable or impractical |
| Granulocytes | 20–24 °C without continuous agitation | Expire 24 hours after collection and are transfused as soon as possible |
| Frozen plasma | −18 °C or colder | Standard dating is 1 year; eligible Fresh Frozen Plasma and Plasma Frozen Within 24 Hours stored at −65 °C or colder may have 7-year dating with FDA approval |
| Cryoprecipitate | −18 °C or colder | Frozen dating is 1 year |
| Frozen red cells | −65 °C or colder | May be stored for as long as 10 years in the licensed high-glycerol system |
Room-temperature platelet storage supports platelet function and also permits rapid bacterial growth. Collection controls, culture-based testing, rapid testing, pathogen reduction, or a permitted combination provides the product-specific bacterial-risk strategy. Seven-day dating requires an eligible container and an FDA-cleared or approved safety strategy. Cold storage is a separate product pathway with its own preparation, label, dating, and clinical-use conditions.6,7
Storage changes
Stored red cells gradually lose adenosine triphosphate and 2,3-diphosphoglycerate, release potassium into the supernatant, change membrane shape and flexibility, and accumulate free hemoglobin. Refrigeration and preservative systems slow deterioration without stopping it. Product inspection, temperature control, hemolysis limits, and labeled dating convert these storage-lesion changes into release controls.3,8
Platelets consume glucose and produce lactate during storage. Rising lactate can lower pH, reduce adenosine triphosphate, change discoid platelets toward spherical forms, diminish visible swirling, and increase activation markers. Visible swirling gives a rough indication of platelet shape. Release also depends on the required pH, yield, bacterial-risk, and process controls. The applicable platelet process must meet a pH of 6.2 or higher at the defined end-of-storage assessment.5,9
Dating and system integrity
A sealed collection set is a closed system. Processing within that system preserves sterility and the original product dating when the licensed instructions permit the step. A validated sterile connection can preserve closed-system status. Opening the system exposes the component to the environment and generally shortens expiration to 24 hours at 1 to 6 °C or 4 hours at 20 to 24 °C. Manufacturer instructions and the facility's validated procedure may set a more restrictive limit.3
Frozen plasma prepared within the time specified for Fresh Frozen Plasma can be stored at −18 °C or colder for 1 year. After thawing, Fresh Frozen Plasma is stored at 1 to 6 °C and expires in 24 hours. A functionally closed unit that remains suitable may be relabeled Thawed Plasma and kept at 1 to 6 °C until 5 days after thaw or its original expiration, whichever comes first. Cryoprecipitate is commonly stored frozen for 1 year. After thawing, a single unit or a prepooled closed-system product expires in 6 hours; a pool made in an open system expires 4 hours after entry, without extending the original post-thaw expiration. Thawed cryoprecipitate must not be refrozen.3
Component preparation and selection
Whole blood can be separated by validated centrifugation and expression steps into red cells, platelets, plasma, and cryoprecipitate. Apheresis collects one or more target components directly. The instrument, collection set, centrifugation program, timing, temperature, and staff procedure form one validated process. Relative centrifugal force depends on both speed and rotor radius, so validated preparation settings are instrument-specific.
The platelet-rich-plasma method begins with a light spin that leaves platelets in the plasma, followed by a hard spin that pellets them. The buffy-coat method begins with a hard spin and recovers the leukocyte-and-platelet layer between the red cells and plasma. Compatible buffy coats may be pooled before final processing. Each method has its own validated timing, temperature, centrifugation, pooling, and storage requirements. FDA's 2024 buffy-coat document gives device manufacturers draft guidance that has not been implemented as a requirement.10
After centrifugation of whole blood, plasma expression leaves a concentrated red-cell component. Nonadditive red cells commonly have a hematocrit near 65% to 80%. An additive solution replaces removed plasma and commonly produces a hematocrit near 55% to 65%. The licensed collection system and facility procedure establish the actual range.3,5
Cellular components
Component selection begins with the laboratory purpose and processing attributes of the product. Recipient testing, compatibility, clinical indication, and emergency status determine final issue.
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| Product | Processing purpose | Laboratory selection or release cue |
|---|---|---|
| Whole blood | Retains red cells and most plasma in one component | Issue through an established whole-blood program; dating follows the collection solution |
| Red blood cells | Concentrates red-cell mass after most plasma is removed | Confirm ABO/D label, compatibility requirements, integrity, temperature history, and expiration |
| Whole-blood-derived platelets | Recovers platelets from one collection, commonly in about 25–50 mL of plasma and commonly followed by pooling | The process targets at least 5.5 × 1010 platelets per unit; the pool retains traceability to every donor |
| Apheresis platelets | Collects a standard target of at least 3.0 × 1011 platelets from one donor, commonly in about 250–300 mL and approximately equal to six whole-blood-derived units | A component below 3.0 × 1011 carries its actual platelet content on the label; verify bacterial-risk control, storage strategy, expiration, and required modifications |
| Granulocytes | Collects granulocytes by apheresis, often after donor stimulation | Release requires the labeled yield, irradiation, ABO considerations, and rapid issue within the 24-hour dating period |
Plasma components and derivatives
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| Product | Preparation | Laboratory selection or release cue |
|---|---|---|
| Fresh Frozen Plasma | Plasma frozen within the licensed time after collection | Retains clinically useful amounts of labile and stable coagulation factors; use the labeled thawed dating |
| Plasma Frozen Within 24 Hours After Phlebotomy | Plasma separated and frozen within 24 hours | Similar broad factor content with lower levels of some labile factors than Fresh Frozen Plasma |
| Thawed Plasma | Eligible thawed plasma relabeled for extended refrigerated storage | Provides broader inventory availability through a total 5-day post-thaw period |
| Liquid Plasma | Plasma separated from whole blood and stored at 1–6 °C without freezing | Dating extends no later than 5 days after the source whole blood expires; factor content changes during refrigerated storage |
| Cryoprecipitated Antihemophilic Factor | Cold-insoluble fraction recovered in about 5–20 mL from thawing eligible plasma | Each component provides concentrated fibrinogen, factor VIII, factor XIII, von Willebrand factor, and fibronectin |
| Plasma Cryoprecipitate Reduced | Supernatant remaining after cryoprecipitate removal | Has reduced fibrinogen, factor VIII, factor XIII, and von Willebrand factor; selection follows the treatment protocol |
Cryoprecipitate is prepared by thawing eligible plasma at 1 to 6 °C until a cold-insoluble precipitate forms. Centrifugation concentrates that precipitate, most supernatant is expressed, and the small residual volume is refrozen within the validated period, commonly within 1 hour. Preparation and labeling preserve the identity of every represented donor.3,5
Plasma derivatives such as albumin, immune globulins, factor concentrates, and Rh immune globulin are manufactured from pooled plasma through industrial fractionation and product-specific pathogen controls. These licensed biologic products carry product-specific concentrations, potency, preparation, storage, and expiration in their package inserts.3,5
Component modifications
The intended product effect and the processing method determine which specification and dating rule applies.3,11,12
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| Modification | Product effect | Release and dating consequence |
|---|---|---|
| Prestorage leukoreduction | Removes most donor leukocytes before their cytokines and cellular debris accumulate | Red cells and apheresis or pooled platelets have fewer than 5 × 106 residual leukocytes; a single leukoreduced whole-blood-derived platelet has fewer than 8.3 × 105 |
| Irradiation | Prevents proliferation of viable donor T lymphocytes | The target dose is 25 Gy at the center of the container with at least 15 Gy throughout; red cells expire at the earlier of their original date or 28 days after irradiation, while platelet and liquid-plasma dating remains unchanged |
| Washing | Removes most residual plasma and soluble material while losing some cells | An open-system washed red-cell component generally expires after 24 hours at 1–6 °C; washed platelets generally expire after 4 hours at 20–24 °C |
| Platelet volume reduction | Removes part of the platelet supernatant when a smaller plasma volume is required | Platelet loss and activation are assessed under the validated method; an open system expires after 4 hours at 20–24 °C |
| Freezing and deglycerolization | Uses glycerol to protect red cells during freezing, then removes glycerol before transfusion | Frozen red cells may retain rare units for as long as 10 years; an open-system deglycerolized unit expires after 24 hours at 1–6 °C, and an approved closed system may permit 14-day dating |
| Rejuvenation | Adds an approved pyruvate-inosine-phosphate-adenine solution to eligible stored red cells to restore 2,3-diphosphoglycerate and adenosine triphosphate14 | Washing removes the inosine before transfusion; the cells are issued or frozen under the product instructions |
| Pathogen reduction | Treats an eligible platelet or plasma product to reduce susceptible pathogens and donor leukocyte activity | Only the approved product, container, process, label, and instructions establish its pathogen claims and expiration |
| Aliquoting or dividing | Produces smaller portions from one parent component | Every division remains traceable to the parent; open processing may shorten dating, while a validated sterile connection may preserve it |
Leukoreduction and irradiation solve different problems. Leukoreduction reduces leukocyte-mediated febrile reactions, alloimmunization, and cytomegalovirus transmission risk. Irradiation prevents transfusion-associated graft-versus-host disease by stopping donor lymphocyte proliferation. Cellular components with an irradiation requirement remain subject to that requirement after leukoreduction. Washed components meet a leukoreduced labeling claim only through a validated leukoreduction process. Granulocytes contain many viable lymphocytes and are irradiated before issue.3,11
Irradiation is controlled as a validated process. A radiation-sensitive indicator confirms that a container was included in an irradiation batch. Dosimetry and scheduled verification establish that the entire load receives the required dose distribution and supply the quantitative dose measurement.12
The common US high-glycerol process uses approximately 40% weight/volume glycerol, slow freezing, and storage at −65 °C or colder for up to 10 years. A low-glycerol method uses approximately 20% glycerol, rapid controlled freezing, and storage near −120 °C with strict temperature stability. Deglycerolization uses sequential solutions of decreasing tonicity to remove the penetrating cryoprotectant without causing osmotic lysis. Glycerolization, freezing, storage, deglycerolization, release testing, and post-thaw dating all follow the licensed system and its validated procedure. Another cryopreservation system follows its own authorization and instructions.3,5,13
Component quality control
Quality control is the planned measurement of products and processes against defined specifications. Quality assurance consists of planned activities that provide confidence in the process, including document control, record review, and deviation investigation. The quality management system connects quality control and quality assurance across collection, testing, processing, storage, release, and records.
Before issue, visual inspection assesses discoloration, clots, leaks, and container integrity. Cell yield, residual leukocytes, potency, bacterial-risk control, and irradiation dose require their specified measurements and records. The quality management system also controls training and competency, equipment calibration and maintenance, suppliers, temperature records, occurrence review, corrective action, assessment, and process improvement. Federal regulations establish legal requirements. AABB standards add requirements for facilities that adopt them or hold AABB accreditation, and the facility procedure turns both sources into the local process.
Product specifications
Current specifications use product-specific sampling and statistical acceptance. The collection system instructions, federal requirements, adopted accreditation standard, and validated facility procedure together define how many components are tested and how a process is judged.12
Federal platelet regulations require monthly testing of four representative whole-blood-derived platelet components from different donors for platelet count, pH, and volume. Other component classes follow their own sampling requirements.1
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| Component or process | Central quality-control specification |
|---|---|
| Leukoreduced red cells | At least 85% of the original red-cell mass is retained; the process demonstrates with 95% confidence that more than 95% of units contain fewer than 5 × 106 residual leukocytes |
| Whole-blood-derived platelets | At least 90% of sampled components contain at least 5.5 × 1010 platelets and have pH of 6.2 or higher at the end of allowable storage |
| Leukoreduced whole-blood-derived platelets | At least 75% of sampled components contain at least 5.5 × 1010 platelets, at least 90% have pH of 6.2 or higher at the end of allowable storage, and the process demonstrates with 95% confidence that more than 95% contain fewer than 8.3 × 105 leukocytes |
| Pooled leukoreduced platelets | At least 90% have pH of 6.2 or higher at the end of allowable storage, and the process demonstrates with 95% confidence that more than 95% contain fewer than 5 × 106 leukocytes; the whole-blood-derived platelet criteria also apply |
| Apheresis platelets | The process demonstrates with 95% confidence that more than 75% of units contain at least 3.0 × 1011 platelets and, with 95% confidence, that more than 95% have pH of 6.2 or higher at issue or within 12 hours after expiration |
| Leukoreduced apheresis platelets | The process also demonstrates with 95% confidence that more than 95% contain fewer than 5 × 106 residual leukocytes |
| Cold-stored apheresis platelets | Validation demonstrates with 95% confidence that more than 75% maintain pH of 6.2 or higher through the labeled storage period, up to 14 days; quality control demonstrates with 95% confidence that more than 95% have pH of 6.2 or higher at issue or within 12 hours after expiration |
| Cryoprecipitated Antihemophilic Factor | Average content is at least 150 mg fibrinogen and 80 IU factor VIII per component or per component represented in a pool |
| Deglycerolized red cells | Mean red-cell recovery is at least 80%, with adequate glycerol removal and free-hemoglobin control under the validated method |
| Granulocytes | At least 75% of tested components contain 1.0 × 1010 or more granulocytes |
| Irradiated cellular components | A validated load pattern delivers 25 Gy to the center and at least 15 Gy to every part of the container, with scheduled dose verification |
Quality-control results are reviewed on the schedule defined for the product. Document a result outside its limit, control the affected product, and investigate the process. Review includes equipment performance, supplies, operator technique, calculations, related components, and the possibility of a trend. Product disposition and process acceptance follow the written procedure and its sampling plan.
Red-cell recovery calculation
Deglycerolization removes glycerol and supernatant while retaining red cells. Processing recovery compares cell content before and after processing. The fraction of transfused cells still circulating in a recipient 24 hours later is a separate measure.13
Hematocrit is a volume fraction. With measured suspension volumes:
red-cell volume (mL) = suspension volume (mL) × hematocrit (L/L)
recovery (%) = postprocessing red-cell volume ÷ preprocessing red-cell volume × 100
Component weight multiplied by hematocrit does not directly give red-cell mass. A weighing method must subtract the container tare and use an appropriate, validated density to convert net suspension weight to volume. Preprocessing and postprocessing suspensions may have different densities.
The final suspension retains 82.5% of the original red-cell volume. Recovery is one specification among several. Before release, review the other product specifications, processing records, and applicable sampling and acceptance criteria.12
Practice
References
- Electronic Code of Federal Regulations. Title 21, §§606.121, 606.122, 610.40, 610.41, 610.53, 640.5, and 640.25. Accessed August 26, 2026. https://www.ecfr.gov/current/title-21/chapter-I/subchapter-F Back to text
- US Food and Drug Administration. Acceptable Circular of Information for the Use of Human Blood and Blood Components. December 2024. Accessed August 26, 2026. Back to text
- Association for the Advancement of Blood & Biotherapies. Circular of Information for the Use of Human Blood and Blood Components. June 2024. Back to text
- International Council for Commonality in Blood Banking Automation. ISBT 128 Standard Technical Specification. Version 6.2.2. April 2023. Back to text
- Bloch EM, Campbell-Lee S, McKenna DH Jr, Montemayor-Garcia C, Schwartz J, Shaz B, Storry J, eds. Technical Manual. 22nd ed. AABB; 2026. Back to text
- US Food and Drug Administration. Bacterial Risk Control Strategies for Blood Collection Establishments and Transfusion Services to Enhance the Safety and Availability of Platelets for Transfusion: Guidance for Industry. December 2020. Back to text
- US Food and Drug Administration. Exceptions and Alternative Procedures Approved Under 21 CFR 640.120(a). May 12, 2023. Accessed September 11, 2026. Back to text
- Yoshida T, Prudent M, D'Alessandro A. Red blood cell storage lesion: causes and potential clinical consequences. Blood Transfus. 2019;17(1):27-52. doi:10.2450/2019.0217-18 Back to text
- US Food and Drug Administration. Guidance for Industry and FDA Review Staff: Collection of Platelets by Automated Methods. December 2007. Back to text
- US Food and Drug Administration. Recommendations for the Development of Blood Collection, Processing, and Storage Systems for the Manufacture of Blood Components Using the Buffy Coat Method. Draft guidance for industry; not for implementation. October 2024. Accessed August 29, 2026. Back to text
- US Food and Drug Administration. Pre-Storage Leukocyte Reduction of Whole Blood and Blood Components Intended for Transfusion: Guidance for Industry. September 2012. Accessed August 26, 2026. Back to text
- Association for the Advancement of Blood & Biotherapies. Standards for Blood Banks and Transfusion Services. 35th ed. AABB; 2026. Effective April 1, 2026. Accessed August 26, 2026. https://www.aabb.org/standards-accreditation/standards/blood-banks-and-transfusion-services Back to text
- Joint Trauma System. Frozen and Deglycerolized Red Blood Cells. Clinical Practice Guideline ID 26. August 5, 2024. Accessed August 29, 2026. Back to text
- DailyMed. Rejuvesol red blood cell processing solution: product label. Description. Accessed September 8, 2026. Back to text