Exam revision May 23 Blood Components Flashcards
Name blood products:
Anything made from blood donation is called a blood product.
- Red cell concentrates (from single donors)
- Platelet concentrates (may be from up to 4 donors of same type or single donor - depends on manufacturing process)
- Fresh frozen plasma (single donor)
- Cryoprecipitate
Plasma derivatives
Critical parts extracted from a pool of blood donation at plasma fractionation centres.
A plasma derivative could be coagulation factors, tetanus toxoid immunoglobulins.
What are the main three components of blood?
WBC
Platelets
Red cells
All suspended in plasma (Yellow fluid) with the cells occupying 40% of the total volume.
Transfusion reactions - how do you know you are having one?
Chills, fever, raise in temperature, tachycardia, pain at site of transfusion, lumbar pain as liver and spleen are processing the blood, chest pain.
Haemolysis looks similar to bacterial infection.
A delayed transfusion Rx can occur within 2 weeks.
Serological rx can happen later than that.
The transfusion would be stopped, a saline drip administered, possible steroids and finding the safest possible unit eg Group O D neg.
What differentiates the pos/neg RH system on blood product labels?
Black lettering is positive.
An outlined letter is negative.
Antigens lacking would be documented.
What is the range of Hb needed for a patient to donate blood?
Male: >135g/L
Female: >125g/L
This ensures over 40g/L per pack.
When can you NOT donate blood?
If you are under 50kg in weight or under 17 yrs old.
Pregnancy in last 9 months.
Infectious illnesses.
IV drug user.
Sex worker.
Therapeutic drugs; aspirin, antibiotics, antihistamines as this effects the function of cells.
When can you NOT donate blood?
If you are under 50kg in weight or under 17 yrs old.
Pregnancy in last 9 months.
Infectious illnesses.
IV drug user.
Sex worker.
Therapeutic drugs; aspirin, antibiotics, antihistamines as this effects the function of cells.
If you have given blood too often within an interval (120 days RBC cycle)
How is blood product kept?
- RBC are kept at 4 degrees C for 35 days.
- Platelets are kept at 22-24 degrees (room temp) for 7 days with bacterial monitoring and agitation to prevent clumping together and gaseous exchange. Platelets like to respire when stored.
- frozen components are stored below -25 degrees and can last 36 months at this temperature.
- Granulocytes are kept at room temp 22-24 degrees and can last for 24 hours. This is used for patients with poor immune status. Not agitated as they will degranulate.
Due to the risk of variant CJD within the UK donor population from meat in 1980’s, all components are leukodepleted to eradicate prions being in the WBCs. This removes the risk of CJD contamination.
Which 4 mandatory test are used for blood donations and which antigen is being detected?
Hep B virus - HBsAg
Hep C virus - Anti-HCV, HCV RNA
HIV - Anti-HIV I and II
Syphilis - Anti-Treponema pallidum
HEV (not mandatory but performed on all donations) - HEV RNA: this is useful to give HEV negative donations to patients who are immunocompromised so that they do not develop HepC.
Donor interviews may highlight a need for further testing; cytomegalovirus or piercing, tattoo,
acupuncture would be tested for Core B antigen or Hep B antibodies. Negative human T-cell in vitro virus is screened once for each donor.
What happens to blood after donation?
All the blood products are divided up after leukodepletion and then stored appropriately.
Who governs blood donation and handling?
Protocols are governed by the GMP - Good Manufacturing Practice to provide a quality system with safe products which are fit for use. All environments are controlled and can be bled into packs within 7.5 hours.
There are international labeling standards so that blood can be shared between countries.
There is a unique donation number which informs of the country of origin, where it was collected and manufactured.
When can blood products not be used?
Controlled handling of blood products:
- Within 7.5 hrs: can use all components.
- Between 7.5 to 8 hrs: can use cellular components but not plasma as it will have begun to coagulate.
- Between 8 - 10 hrs: red cells can be used but no platelets or plasma can be used.
- More than 10 hrs: the contents would have to be checked to see if they were suitable for use.
When would red cells in additive solution be used?
- Acute blood loss >30%.
- If further blood loss is predictable (hemorrhage, critical care).
- Post-chemotherapy.
- Radiotherapy.
- Chronic anemia.
- Known GVHD or significant risk factors for GVHD (graft versus host disease).
Red cells would be kept at 4-6 degrees for 35 days.
When would platelets be transfused and what would the dose be?
If a patients platelet count drops below 10, or there is an additional risk of sepsis or if their is bleeding due to platelet dysfunction then:
1 x ATD (adult therapeutic dose) would be transfused to maintain platelets at around 70 x 10E9/l. The dose will cause the patient’s platelets to increase by 10 x 10E9.
