Study guide
3.2 Anticoagulants, Additives, and Storage Temperatures
Scientist in Blood Banking, BB ASCP
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1 Introduction & Exam Overview
1.1 Current Exam Facts 1.2 Eligibility Routes and Application 1.3 CMP, Credential Citation, and BB vs SBB
2 Donors and Collection
2.1 Donor Qualification 2.2 Collection Methods and Adverse Reactions 2.3 Special Donations
3 Processing, Storage, and Component QC
3.1 Processing: FDA/AABB Requirements, Testing, and Labeling 3.2 Anticoagulants, Additives, and Storage Temperatures 3.3 Transportation, Stored-Product Properties, and Expiration 3.4 Blood Component Quality Control
4 Blood Components
4.1 Red Blood Cells, Whole Blood, Washed, Frozen, and Rejuvenated 4.2 Platelets, Plasma, and Cryoprecipitated AHF 4.3 Granulocytes, Leukoreduced, and Irradiated Components 4.4 Apheresis Products, Fractionation, and Hematopoietic Progenitors
5 Blood Group Genetics and Transfusion Role
5.1 Basic and Molecular Genetics 5.2 Inheritance of Blood Groups 5.3 Immunogenicity and Antigen Prevalence
6 ABO and Lewis Systems
6.1 ABO Biochemistry and Antigens 6.2 ABO Antibodies, Discrepancies, and Subgroups 6.3 Lewis System
7 Rh System
7.1 Rh Genetics and Antigens 7.2 Weak D, Partial D, and Rh Antibodies 7.3 Rh Phenotyping and Clinical Significance
8 Kell, Duffy, Kidd, and MNS
8.1 Kell System 8.2 Duffy System 8.3 Kidd System 8.4 MNS System
9 Additional Systems and Antigens
9.1 P1PK, Globoside, and Ii Systems 9.2 Lutheran and Other Blood Group Systems 9.3 High- and Low-Prevalence Antigens 9.4 HLA, Platelet-Specific, and Granulocyte-Specific Antigens
10 Immunology Foundations
10.1 Immune Response, B and T Cells, Macrophages 10.2 Immunoglobulins: Classes, Structure, and Properties 10.3 Antigen-Antibody Interactions and Testing 10.4 Complement Pathways and Biologic Properties
11 Physiology, Hemostasis, Cytopenias, and Transplantation
11.1 Physiology of Blood 11.2 Hemostasis and Coagulation 11.3 Immune and Nonimmune Cytopenias 11.4 Solid Organ and HPC Transplantation
12 Hemolytic Disease of the Fetus and Newborn
12.1 HDFN Pathophysiology 12.2 HDFN Detection 12.3 HDFN Treatment and Prevention
13 Routine Serologic Testing
13.1 Blood Grouping Tests 13.2 Antibody Detection 13.3 Compatibility Testing and Crossmatch 13.4 Direct Antiglobulin Testing
14 Antibody Identification
14.1 Antibody Identification and Rule-Out 14.2 Clinical Significance, Dosage, and Multiple Antibodies 14.3 Panel Problem-Solving and Common Traps
15 Reagents and Special Techniques
15.1 Antiglobulin Sera, Grouping Sera, and Reagent Red Cells 15.2 Enzymes, Enhancement Media, and Lectins 15.3 Adsorption, Elution, Titration, and Cell Separations 15.4 Molecular, Solid-Phase, Column, ELISA, and Related Methods
16 Serologic QA and Special Reagents
16.1 Blood Sample Quality Assurance 16.2 Reagent and Procedure Quality Assurance 16.3 Thiol Reagents, Neutralization, Chloroquine, EGA, and Immunofluorescence
17 Indications and Component Therapy
17.1 Indications for Transfusion 17.2 Red Cell and Whole Blood Therapy 17.3 Platelet, Plasma, and Cryoprecipitate Therapy 17.4 Special Component Therapy
18 Adverse Effects of Transfusion
18.1 Immunologic Transfusion Reactions 18.2 Nonimmunologic Transfusion Reactions 18.3 Transfusion-Transmitted Diseases
19 Apheresis, Administration, and Patient Blood Management
19.1 Apheresis and Extracorporeal Circulation 19.2 Blood Administration 19.3 Patient Blood Management
20 Laboratory Operations
20.1 Quality Assessment and Troubleshooting 20.2 Quality Control, Proficiency Testing, and Regulation 20.3 Laboratory Safety 20.4 Laboratory Mathematics and Instrumentation
3.2 Anticoagulants, Additives, and Storage Temperatures
Key Takeaways Explain This Topic AI
CPD or CP2D red cells outdate at 21 days; CPDA-1 (adenine added) at 35 days; AS-1, AS-3, AS-5, and AS-7 additive-solution red cells at 42 days (21 CFR 610.53).
Standard whole-blood collection is about 450 mL into 63 mL CPD/CPDA-1 (or 500 mL into 70 mL); additive solutions are about 100–110 mL added after most plasma is removed; ACD-A is the usual apheresis anticoagulant.
Storage temperatures are product-specific: RBC/whole blood 1–6 °C; platelets 20–24 °C with continuous gentle agitation; FFP/PF24/cryo frozen at ≤ −18 °C; thawed plasma 1–6 °C; thawed cryo 20–24 °C; granulocytes 20–24 °C without agitation for 24 hours; frozen glycerolized RBCs ≤ −65 °C.
Transport is not the same as storage: red cells may ship at 1–10 °C in a validated container, then must return to 1–6 °C storage on arrival.
Apheresis ACD-A and additive solutions are not interchangeable labels; the bag’s licensed anticoagulant/additive determines both the expiration and the expected hematocrit.
Last updated: August 2026
Anticoagulant-preservative solutions do two jobs at once: they stop the donated blood from clotting, and they feed red-cell metabolism long enough for a licensed dating period. The BB exam treats the solution name on the bag as a dating key, not as trivia. 21 CFR 610.53 is the federal dating table. AABB Standards and the Circular of Information use the same numbers.
Primary anticoagulants
CPD (citrate-phosphate-dextrose) is the classic whole-blood anticoagulant. Citrate binds ionized calcium so the coagulation cascade cannot run. Phosphate buffers hydrogen ion produced during storage. Dextrose is the glycolytic substrate red cells use to make ATP. Without additive solution, CPD (and CP2D, which contains extra dextrose) supports 21-day red-cell or whole-blood storage at 1–6 °C.
CPDA-1 is CPD plus adenine . Adenine supports the salvage pathway that replenishes ATP. That extra nucleotide is why CPDA-1 red cells and whole blood are licensed for 35 days at 1–6 °C. The exam stem that asks “why does adenine extend dating from 21 to 35 days?” is asking for ATP maintenance, not for a change in citrate strength.
ACD-A (anticoagulant citrate dextrose, solution A) is the usual anticoagulant in apheresis circuits. It is metered into the draw line so ionized calcium falls only in the extracorporeal blood, not in the donor’s entire plasma volume. ACD-A is not the routine 35- or 42-day red-cell bag label. If an apheresis red-cell unit is stored, dating follows the licensed collection-set and additive combination, not a CPD assumption.
Heparin is not a routine licensed RBC storage anticoagulant. If you see heparin on an exam item, it is almost always a cell-processing or specialized-collection distractor, not a 42-day packed-red-cell answer.
Additive solutions and 42-day red cells
After most plasma is removed, an additive solution is run onto the packed red cells. The extra volume lowers hematocrit into the mid-50s to mid-60s, supplies more dextrose and adenine, and includes a membrane-protective solute. Licensed U.S. additives you must recognize:
- Solution Common name Distinctive solutes Typical volume RBC dating
- CPD or CP2D Primary anticoagulant only Citrate, phosphate, dextrose 63 mL / 450 mL blood 21 days
- CPDA-1 Primary + adenine CPD + adenine 63 mL / 450 mL blood 35 days
- AS-1 Adsol Adenine, dextrose, mannitol, NaCl ~100 mL 42 days
- AS-3 Nutricel Adenine, dextrose, citrate, phosphate, NaCl (no mannitol) ~110 mL 42 days
- AS-5 Optisol Similar to AS-1 (mannitol present) ~100 mL 42 days
- AS-7 SOLX Phosphate and bicarbonate buffer system ~110 mL 42 days
- ACD-A Apheresis circuit Citrate + dextrose Metered ratio in the kit Per licensed set
AS-1 and AS-5 use mannitol to reduce storage hemolysis. AS-3 uses extra citrate instead of mannitol and is the additive often paired with CP2D collections. AS-7’s bicarbonate/phosphate buffer better preserves 2,3-DPG than older additives, but its licensed dating is still 42 days , not a longer federal dating period. Do not invent a 49-day AS-7 shelf life unless a specific licensed container’s instructions for use say otherwise—and 21 CFR 610.53 still lists additive-solution red cells at 42 days.
Typical additive-solution hematocrit is about 55–65%. CPDA-1 packed cells, which keep only a small residual plasma volume, run higher—classically up toward 70–80%. That is why CPDA-1 red-cell QC includes a hematocrit ceiling (see 3.4).
Volume ratios
The licensed ratio matters because too much citrate relative to blood is a poor preservative environment and a citrate-toxicity risk if the plasma is transfused. The teaching collection is 450 mL ± 10% whole blood into 63 mL CPD or CPDA-1 , or 500 mL into 70 mL . Additive solution is then about 100 mL (AS-1/AS-5) or 110 mL (AS-3/AS-7) after plasma removal.
A low-volume collection (below the manufacturer’s acceptable range, often taught as less than about 300 mL or less than 90% of the intended draw) has excess anticoagulant. Those units are not processed as standard red cells unless the facility’s FDA-approved procedure allows a labeled low-volume product. Overfills risk clots and under-anticoagulation. Both are processing failures, not “close enough” units.
Apheresis ACD-A is delivered at the kit’s programmed whole-blood-to-anticoagulant ratio, commonly near 1:10 to 1:12. The operator does not pour 63 mL of ACD-A into a 450 mL bag and call it CPD. If the instrument alarms for a ratio fault, the product is evaluated against the set’s instructions, not converted by mental arithmetic to a CPD dating period.
Storage temperatures — product by product
Temperature is a product specification, not a room preference. 21 CFR 640.4, 640.11, 640.24, 640.25, 640.34, and 640.17, together with AABB storage tables, give the following operational map:
- Product Storage temperature Other storage rule Usual dating driver
- Whole blood / RBCs 1–6 °C No agitation required 21 / 35 / 42 days by solution
- RBCs in transit 1–10 °C Validated shipping container Transport only; return to 1–6 °C
- Apheresis or whole-blood platelets 20–24 °C Continuous gentle agitation 5–7 days + bacterial strategy
- FFP, PF24, cryoprecipitate (frozen) ≤ −18 °C Must remain solidly frozen Typically 12 months at −18 °C
- Frozen RBCs (glycerol) ≤ −65 °C Cryoprotectant present Years, per licensed method
- Thawed FFP (first 24 h) / thawed plasma 1–6 °C Relabel after 24 h if kept 24 h as FFP; thawed plasma to 5 days
- Thawed cryoprecipitate 20–24 °C Do not refrigerate after thaw 6 h single; 4 h if pooled open
- Granulocytes 20–24 °C No agitation ; 24-hour product Transfuse as soon as possible
Why those temperatures exist. Red cells stored at 1–6 °C slow glycolysis and bacterial growth while remaining above freezing. Platelets need room temperature to maintain discoid shape and gas exchange through the bag; refrigeration injures platelet membranes (the cold-storage lesion) and, for conventional room-temperature platelets, continuous gentle agitation keeps them in suspension and supports gas exchange. Frozen plasma and cryoprecipitate must stay at or below −18 °C so labile factors do not decay and so the product does not partially thaw. Frozen glycerolized red cells require ≤ −65 °C (21 CFR 640.17) because that is the temperature that keeps high-glycerol red cells stable in a mechanical freezer. Granulocytes are metabolically fragile, are stored at 20–24 °C without agitation, and expire 24 hours after collection.
PF24 is plasma frozen within 24 hours after collection (or within the licensed system’s timeframe) and then stored like FFP at ≤ −18 °C. Once frozen, storage temperature is the same as FFP; the difference is manufacturing time to freezer, not the freezer setpoint.
Some establishments store FFP at ≤ −65 °C. Twelve-month dating at ≤ −18 °C is the routine FDA/Circular figure. Longer dating at colder temperatures requires a licensed or approved condition; do not assume a 7-year date unless the facility’s approved procedure and label support it.
Transport versus storage
This distinction is tested constantly. Storage of red cells and whole blood is 1–6 °C. Transport of those same products is 1–10 °C in a validated shipping container (21 CFR 640.2(c)(3) for reissue; AABB transport tables use the same range). A courier box that arrives at 8 °C is in range for transport. Dumping those units onto a 20 °C counter “because they were already warm in the box” is a storage violation. On arrival, move them into a monitored 1–6 °C refrigerator.
Platelets ship as close as possible to 20–24 °C. They do not go on wet ice. A validated platelet shipper is designed to hold room temperature, not to refrigerate. Frozen products ship on dry ice or in a qualified frozen system that keeps them solidly frozen; a thawed corner is a manufacturing deviation, not a “soft freeze.”
Granulocytes ship at 20–24 °C without ice and without a platelet agitator. They are issued for immediate transfusion, not for overnight inventory.
Worked scenario. A CPDA-1 whole-blood unit collected at 09:00 is processed into red cells without additive solution and stored at 4 °C. Dating is 35 days, not 42. The same collection, if plasma is removed and AS-1 is added in a closed system, becomes a 42-day red-cell unit. Shipping that AS-1 unit to a trauma center at 9 °C in a validated container is acceptable transport. Leaving it in the ER unmonitored at room temperature after arrival is not storage at 1–6 °C.
Exam traps. CPD is 21 days, CPDA-1 is 35, additive solutions are 42 — do not swap those three numbers. Platelets need agitation; granulocytes do not. Frozen RBCs are ≤ −65 °C, not ≤ −18 °C. Transport 1–10 °C is not permission to store red cells at 8 °C in the blood bank refrigerator.