1. Blood Components MLAB 2431 Immunohematology
Unit 2
Blood Components
MLAB 2431 Immunohematology

2. Blood Collection Maintain viability and function of the blood
Minimize bacterial contamination
Use of a closed system provides sterile blood collection
Anticoagulants used in preservation process
Prevent blood clotting
Preservatives provide nutrients for cells

3. Anticoagulants

4. Additive Solutions
Currently four solutions have been approved by the FDA
Added to the RBCs to increase shelf life (expiration date) to 42 days
AS-1 (Adsol)
AS-3 (Optisol)
AS-5 (Nutricel)
AS-7 (SLOX)
Review Table 15.1, page 345 in book
Nutrients and additives provide a 75% recovery of the RBCs at expiration.
At least 75% of transfused cells remain in circulation 24 hours after transfusion.

5. The Storage Lesion
When blood is stored at 1-6°C, biochemical changes occur
Changes are called the storage lesion
Viable number of RBCs will decrease
Affects the oxygen dissociation curve…the increased affinity of hemoglobin for oxygen.
Low 2,3-DPG, increased oxygen affinity, less oxygen released
pH drops causes 2,3-DPG levels for fall
Once transfused RBCs regenerate ATP and 2,3-DPG after hours
While the storage lesion is significant, neonates are the only group of patients that require “fresh” blood (less than 7 days old). This is done to maximize the 2,3-DPG levels and avoid high potassium and low pH levels.

6. Summarize Storage Lesion
Summary of biochemical changes
pH decreases
2,3-DPG decreases
ATP decreases
Potassium increases
Sodium decreases
Plasma hemoglobin increases

7. Component Preparation
Collection is within 15 minutes, preventing coagulation
Centrifuge at low speed for platelet rich plasma
Remove platelet rich plasma
Centrifuge platelet rich plasma at high speed to remove plasma
Freeze plasma within 8 hours
Some plasma units thawed at 1-4°C-precipitant forms, centrifuge, express plasma leaving cryoprecipitate.
Cryoprecipitate and plasma stored at -18°C
Sterile docking stations join tubing to add satellite bags maintaining original expiration of components
One unit of blood can yield the following: Packed RBCs, FFP, cryo, and platelets. Only the components needed by the patient are transfused.

8. Donor Blood Inspection/Disposition
Units are inspected before issuing for a patient
The following may indicate an unacceptable unit:
Red cell mass looks purple or clots are visible.
Zone of hemolysis observed just above RBC mass, look for hemolysis in segments, especially those closest to the unit – possible bacterial contamination
Plasma or supernatant plasma appears murky, purple, brown or red.
A greenish hue need not cause a unit to be rejected.
Inspect platelets for aggregates.
Inspect FFP and cryo for signs of thawing or cracks in bag and unusual turbidity (i.e. extreme lipemia)

9. Donor Blood Inspection/Disposition
If a unit's appearance looks questionable do the following:
Quarantine unit until disposition is decided.
Gently mix, allow to settle and observe appearance.
If bacterial contamination is suspected the unit should be cultured and a gram stain performed.
Positive blood cultures usually indicative of:
Inadequate donor arm preparation
Improper pooling technique
Health of donor - bacteremia in donor
If one component is contaminated, other components prepared from the same donor unit may be contaminated.

10. Storage Temperatures Packed red blood cells 1 - 6°C
Platelets – Room temperature (20-24°C)
Granulocytes – Room temperature (20-24°C)
Cryoprecipitate (cryo) – THAWED – Room temp (20-24°C)
Frozen plasma - <= -18°C
Plasma thawed stored 1-6°C

11. Storage and Transportation
Transportation of blood and plasma is at 1-10°C
Transportation of platelets and cryoprecipitate is at room temperature
All containers must be quality controlled and validated for temperature control – my use a monitor on the units
Frozen blood components
Dry ice is used
RBC units are at room temperature once released to the responsible person (i.e. nurse)
Must be returned to blood bank if not started on patient in 30 minutes
After 30 minutes, the unit is quarantined and returned to blood center
If units are in proper containers and in surgery or ER for a longer period of time, the units are temperature monitored. There are several types of containers used to transport units and several different types of monitoring methods.

12. Transfusion Practices
Transfusion requires doctor’s prescription-ALWAYS
All components administered through a filter
Must be transfused within 4 hours
Universal donor
Red blood cells are group O
Plasma AB
Universal recipient (patient)
Blood type AB

13. What types of products are transfused?

14. Red Blood Cells Commonly called
Packed red blood cells or leukocyte poor red blood cells – the white blood cells are always filtered out of the units of blood
Leukocytes can induce adverse affects during transfusion, primarily febrile, non-hemolytic reactions.
Reactions to cytokines produced by leukocytes in transfused units.
Other explanations to reactions include: immunization of recipient to transfused HLA or granulocyte antigens, micro aggregates and fragmentation of granulocytes.
Abbreviations you will see in the field: pRBC or LRBC
Hematocrit in the unit is approximately 80% for non-additive (CPD) and 60% for additive (ADSOL)

15. Washed RBCs
Physicians may request washed RBCs to removes plasma proteins, platelets, and microaggregates which may cause febrile of urticarial reactions
Patient may be deficient in IgA and have IgA antibodies
Instrument washed cells 3 times with saline and the unit is labeled as washed RBCs.
Unit expires in 24 hours

16. Frozen RBCs to Deglycerolized RBCs
Blood may be frozen
Rare types
Stock pile for military mobilization/disasters
Blood drawn into anticoagulant preservative
Plasma removed and glycerol added – unit frozen
Blood expiration
Frozen – 10 years
After deglycerolization, 24 hours
Storage temperature
High glycerol -65°C
Low glycerol -120°C, using liquid nitrogen storage

17. Frozen RBCs to Deglycerolized RBCs
Frozen unit thawed at 37°C, thawed RBCs will have high concentration of glycerol.
A solution of glycerol of lesser concentration of the original glycerol is added.
This causes glycerol to come out of the red blood cells slowly to prevent hemolysis of the RBCs.
After a period of equilibration the unit is spun, the solution is removed and a solution with a lower glycerol concentration is added.
This procedure is repeated until all glycerol is removed, more steps are required for the high glycerol stored units.
Unit is washed and new expiration date = 24 hours

18. Platelets
Prevent spontaneous bleeding or stop bleeding in thrombocytopenic patients
Prepared two different methods
Single unit of platelets from one unit of whole blood
This method requires a therapeutic dose of ~10 units
Units must be entered and pooled together
Expiration date is 5 days as a single unit, once pooled together, 4 hours
Apheresis Platelet Concentrate
Prepared by apheresis – platelets removed from blood and blood given back to donor
One unit equals the same amount as the ~ 10 single units (1 therapeutic dose)
Decreases patient exposure to many different donors’ platelets and HLA antigens
Expiration date is 5 days
Storage is at °C with constant agitation

19. Apheresis

20. Granulocytes Rarely used for transfusion practices
Patients are usually severely immunosuppressed and have serious infections
Neutropenia (<500 WBC/uL)
Documented infections
Gram-negative bacteria
Fungi
Lack of response to antibiotics
Product is irradiated to prevent GVHD
Prepared by hemapheresis
Store at °C
Expiration is 24 hours and infuse ASAP

21. Fresh Frozen Plasma (FFP)
Purpose – to replace labile and non-labile coagulation factors in massively bleeding patients or bleeding from clotting factor deficiencies
Frozen within 8 hours of collection
Expiration
Frozen – 1 year at <-18°C
Frozen – 7 years at <-65 °C
Thawed – 24 hours/stored at °C
Thawed in a °C water bath or FDA approved microwave
Must be ABO compatible with patient
Thawed – can be relabeled as “thawed FFP” and stored for 1 – 5 days at °C*
*FDA does not recognize the practice of thawed plasma being relabeled; however, while it cannot be licensed with the FDA, it can be used by individual transfusion services

22. Cryoprecipitate (Cryo)
Insoluble portion of plasma that precipitates when FFP is thawed at 1 - 6°C
Contains high levels of Factor VIII and fibrinogen
Used for patients in DIC or low fibrinogen levels
Can be used for treatment of hemophiliacs and VonWillebrands when concentrates are not available
Therapeutic dose for an adult is ~6 to 10 units
ABO compatible preferred but not required
Storage temperature
Frozen <= -18°C for 1 year
Thawed – 6 hours
Once pooled – 4 hours (must be pooled into one bag)

23. Irradiation of Blood Components
Cellular blood components are irradiated to destroy viable T- lymphocytes which may cause Graft Versus Host Disease (GVHD).
GVHD can be acute or chronic
GVHD is a disease that results when immunocompetent, viable lymphocytes in donor blood engraft in an immunocompromised host, recognize the patient tissues as foreign and produce antibodies against patient tissues, primarily skin, liver and GI tract. The resulting disease has serious consequences including death.

24. References
alproductsandtobacco/cber/
AABB Technical Manual, 18th edition.