Blood Bank Exam 3 Flashcards
pRBC unit volume
250 mL
Whole Blood unit volume
450 mL
HLA Antigens
Antigens associated with leukocytes, especially important in transplant patients
Irradiating blood components
- eliminates T cells
- prevents graft vs. host
- Directed units from blood relatives
Frozen RBC
- <180 mL
- must wash to remove glycerol
- Expires 24 hours after thaw and wash
Washed RBCs
- prevent allergic reaction
- expires 24 hours after wash
FFP
- 1 year expiration
- 220 mL
- Must be ABO compatible
- does not care about Rh compatibility
Cryo
- “Cryoprecipitate”
- Concentration of Factors: VIII, I, Vwf, XIII
- 15 mL
- Frozen at 18C or lower
- Expires 6 days after thaw (store at RT)
- Must be ABO compatible
Factor Concentrates
- handled by pharmacy
- one factor at a time
- ABO not an issue
Platelet Concentrates
- 300 mL
- ABO compatible if possible
- Avoid Rh pos units given to Rh neg patients
Compatibility Testing sample
- labeling + armband
- no hemolysis
- XM sample expires after 72 hours
- sample kept for 7 days after transfusion
Neonate transfusion requirements
- Low volume (50-80 mL)
- Fresh (<7 days old, low K+, high 2,3 DPG)
- prewarmed units
- CMV negative
- Irradiated
Donor testing
- infectious diseases
- ABO/Rh
- weak D
- antibody screen (if antibody, not for transfusion)
- DAT?
Major Crossmatch
Patient serum + donor cells
Minor Crossmatch
Patient cells + donor serum
Abbreviated Crossmatch
- IS testing only
- no history or evidence of antibody EVER
Extended Crossmatch
- IS and AHG testing
- history or evidence of antibody
Computer Crossmatch
- no testing, computer runs an algorithm
If there is an unexpected incompatibility
you must investigate!!!
Possible causes of incompatibility
- ABO
- Autoantibody
- Alloantibody
- Positive DAT on donor cells (slipped through collection screening)
- Rouleaux
Whole Blood compatibility
Must meet both RBC and plasma compatibility requirements
How long can blood be returned after it is checked out if not used?
30 minutes
How many units triggers a massive transfusion protocol?
5 units
Describe a massive transfusion protocol
- 1 unit FFP per unit pRBCs (catch up if needed)
- 1 unit platelets and 1 unit cryo every 10 units
Name for massive transfusion in neonates
Exchange Transfusion
Emergency Transfusion allows
uncrossmatched O negative pRBCs to be given
Who can receive uncrossmatched O positive pRBCs in an emergency?
Males and women over 65
TACO
- “Transfusion Associated Circulatory Overload”
- most common in elderly and infants
TRALI
- “Transfusion Related Acute Lung Injury”
- Anti-WBC antibodies
PTP
- “Post Transfusion Purpura”
- platelet allo-antibody
- depletion of platelets and coag factors
Immediate Intravascular Hemolysis
- IgM (via complement), IgG, or ABO mixup
- anti-A, K, Jka, Fya are most common
we don’t talk about Bruno nonono
Delayed Extravascular Hemolysis
- anamnestic response
- Rh antibodies, anti-Jka, K, Fya
- 3-7 days post txn
Damage to Transfused Cells
- Heat Damage (blood warmers, storage)
- Physical Damage (pumps, heart valves, ECMO)
What would indicate a “dead” unit on visual inspection?
Brown, purple, clotted, or severely hemolyzed
Proceed to Extended Evaluation if:
- Discrepancy in Clerical Check
- Post DAT pos and pre DAT neg or weaker
- Visual hemolysis in post sample
- Post serum HGB is 20mg/dL higher than Pre
If there are RBCs in the urine with a transfusion reaction
it likely is unrelated to the reaction
Transfusion Reaction Reporting
- physician
- blood bank director
- accrediting agencies
- (if fatal) FDA
- (if fatal) Center for Biologic Evaluation & Research
If a post-transfusion reaction sample is hemolyzed
call for second collection to eliminate possibility of phlebotomist error
Febrile Transfusion Reaction
- > 1 degree C rise in temp (fever)
- anti-WBC antibody (complement activated)
Erythroblastosis fetalis
neonate with HGB <15 g/dL
Kernicterus
brain damage from extremely high bilirubin, usually in neonates
What types of HDN require antibody titers?
Rh and ‘other’
Critical antibody titer level
1:32
How can you tell allo-anti-D from Rhogam on an IAT?
You can’t. You need patient history.
Rhogam dosage during term
- 50 ug at <12 weeks
- 300 ug at >= 12 weeks
What indicates need for transfusion on the Liley graph?
zone 3
What in amniotic fluid can indicate severity of HDN?
bile pigment, measured with optical density at 450 nm
PUB sample testing
- “Percutaneous Umbilical Blood”
- needle guided with ultrasound, drawn from umbilical vein
Fetal Lung Maturity
Ratio of Lecithin to Sphingomyelin (L/S Ratio)
- >2.0:1 = mature
- 1.5:1 = 40% chance of respiratory distress
- <1.5:1 = 70% chance of respiratory distress
FMH Screen
- “Fetal Maternal Hemorrhage”
- Positive = >15mL fetal bleed, reflex to KB stain
KB Stain
- “Kleihauer Betke”
- count 4k cells, determine % fetal cells
1 vial of Rhogam covers
15 mL pRBC or 30 mL WB
Rhogam dosage calculation
(% fetal cells x 50) / 30
Round Up