Platelets/Granulocytes Flashcards
Platelet normal value
150,000-350,000/ul
What platelet conc may cause spontaneous hemorrhage?
Plt < 10,000/ul
What platelet conc can minimize hemorrhage during surgery?
Plt > 50,000/ul
Platelet roles in hemostasis
- Platelet plug
- Stabilize plug by fibrin formation
- Maintenance of vascular integrity
Why transfuse platelets?
- To increase platelet count
- Prophylactically for oncology/chemo pts
- If patients plts not functioning (PFA test)
Refractory
Failure to achieve acceptable plt count following plt transfusion
Efficacy calculation
Clinical count increment (CCI)
Why are platelets sensitive?
- Must be rocked or they will die bc need oxygen transfer in bag to maintain pH
- Jostling too hard or overheating will activate them and then they will die
What happens when platelet activates during storage?
- ATP released
- Plts aggregate
- Increase glucose consumption/lactic acid conc
- Decrease pH, plts swell
Platelet storage conditions
20-24°C
room temp
How does cold storage affect platelet viability?
Irreversible spherical shape change
Platelet expiration date
- 5 days post-collection
- Increased chance of bacterial contamination at storage, length of time, pH
Platelet additive solution (PAS)
Reduces plasma stored with platelets up to 60% (less transfusion reaction)
7-day platelets must be tested for _____
Must be tested for bacterial contamination on day of transfusion
How to store frozen platelets?
DMSO stored up to 2 yrs, 33% viable
How to inactivate pathogens?
- UV light or alkylating agents damage DNA and impair replication (good for viruses, bacteria, fungi, protozoa, and leukocytes but NOT prions)
List steps of prepping platelets from random donor
- Whole blood collected and must now prepare plts within 4 hrs of collection
- Centrifuge w short/light and heavy spins
- Rest 1-2 hrs to unclump and place onto agitator/rocker for storage up to 5 days
- Sterile docking pools of 4-6 different donors
- Test for bacterial contamination thru blood culture or Virax (3 days post collection)
Platelet count and pH QC
- plt count > 5.5 X 10 ^10
- pH > 6.2
Leukoreduced platelets WBC count
WBC < 5 X 10^6
Anticoagulant in apheresis
Citrate
Binds calcium to prevent coag
Body compensates by releasing more calcium and metabolizing citrate
Apheresis centrifugation types
- Intermittent flow (IFC): 1 venipuncture
- Continuous flow (CFC): 2 venipuncture sites
Apheresis filtration
Used instead of centrifugation to remove non-cellular plasma
Apheresis therapeutic uses
Plasma exchange
Pheresis (cell removal)
Apheresis adverse effects
- citrate toxicity
- hypotensive reactions
- hematoma (vascular access complications)
Platelet apheresis donor qualifications
- must meet RBC donor qualifications
- plt count > 150,000
- not taking aspirin (2 day deferral) or plavix (14 day deferral)
Interval between platelet apheresis donations
days > 2
Platelet bag visual inspection
- hemolysis (RBCs > 2ml must be crossmatched)
- bubbles
- clots/aggregates
- color
What do green, yellow, and orange platelet colors indicate?
Green = contraceptives
Yellow = icterus
Orange = Vit A
How to handle granulocyte products
- Stimulate with corticosteroids or CSF
- Must be transfused asap from collection < 24 hrs
- ABO type match
Granulocytes collected from
whole blood or apheresis
Granulocytes used for
Neutropenic pt transfusions to fight infection (must be irradiated and NOT leukoreduced
How to handle hematopoietic progenitor cells (HSCs)
- Growth factors given to pt 4-5 days prior to collection by apheresis or BM
- Cryopreserved/collected in advance
HSCs used for
- stimulating cellular growth after chemo or immune depression
- HLA type match
Plt pre-transfusion testing required
- ABO/Rh type performed per admission
Plt pre-transfusion testing not required
- Crossmatch
- Ab screen
- ABO match
Pre-transfusion labeling
- Unique donor ID
- Expiration date
- Donor blood type/Rh
- E-code
- CMV neg
- Irradiation indicator
- Component assignment tag
HLA expresses what proteins
MHCI, MHCII, and MHCIII
HLA clinical importance
- disease association
- transplant
- plt transfusion
How to read HLA genes
Locus A-D
Subregion P-R
Serologic reactivity 00-99
HLA genetics
- Inherited via haplotype
- Linkage disequilibrium
Are HLA alleles antithetical?
No
T/F HLA genes are highly polymorphic
True
HLA MHCI
- found on all nucleated cells (important for plts/transplants)
- Bind CD8 cells after presenting proteins from intracellular attack
HLA MHCII
- found on only antigen presenting cells, B cells, and T cells (paternity testing)
- Bind CD4 cells and present exogenous proteins
HLA serology testing
- Crossmatch recipient plasma against donor RBC
- HLA antibody screen
- HLA match (recipient and/or donors tested for HLA antigens)
- Type plts for A,B, C and stem cells type for A, B, DR
What is CREG?
Cross-reactive group
HLA clinical importance
- Transfusion
- Transplant matching
- Associated with autoimmune disease
- Paternity testing
What is more immunogenic in HLA match?
Leukocytes
Refractoriness cause in HLA match?
- Contaminating lymphs in product
- May have platelet Ab
T/F HLA serological crossmatch required
False
May not require
Should be matched in MHCI
Platelet crossmatch specific for ___
anti-platelet Ab
Platelet crossmatch tested by ___
testing plt donors against recipient plasma by solid phase method
T/F Plt crossmatch shows both HLA and platelet incompatibility
True
