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- diverts the first 30-45 mL of blood,
- retains skin plug, and
- prevents bacterial contamination
Why plasma from low volume units cannot be transfused?
because of the abnormal anticoagulant/plasma ratio
why is knowing the specific gravity of different blood cells helpful?
to develop centrifugal conditions for optimal cells separation and collection.
needed to convert weight of component (g) to the volume (mL)
What is the volume of blood collected during routine phlebotomy?
450 +/- 10% or 500 +/- 10%
- bright red blood
- rapid collection (within 4 minutes)
- pulsating needle
Plasma frozen within 24 Hours after Phlebotomy
plasma separated from WB and placed in the freezer within 8-24 hours
3 major variables that affect recovery of cells from WB by differential centrifugation are:
- rotor size
- centrifuge speed
- duration of centrifugation
Primary separation by centrifugation
- PRP and RBCs are separated
- PRP is removed into another container
2nd separation by centrifugation
- Higher g forces used on PRP container
- Platelets are turned into a pellet
- PPP transferred to another container
- pellet left in 40-70 mL of PPP for 1 Hr
Shelf life and hematocrit of CPD- or CP2D-preserved RBCs
What amount of AS is added to RBCs?
450 mL WB collection-->100 mL AS
500 mL WB collection-->110 mL AS
shelf life and Hct of CPDA-1 preserved RBCs
What is commonly used for neonatal or pediatric transfusions?
<7 to 10 days old
What influences clumping in platelets?
Temp at which they are prepared
Platelets prepared at 24C , show least amount of clumps
what amount of RBCs is present in a unit of platelets?
What are the 2 major methods used in preparing platelets from WB?
- Buffy coat method-->Europe &
Fresh Frozen Plasma
plasma separated from WB and placed in the freezer within 8 Hrs of collection
How can rapid freezing of plasma be accomplished?
Mixture of dry ice with either ethanol or antifreeze
What can be done to an FFP bag before freezing, to recognize inadvertent thawing?
Place a rubber band around the bag
press a tube against the bag to create indentation
which coagulation factors are reduced in Thawed Plasma prepared from FFP?
Factor V (>60%)
Factor VIII (>40%)
Can be separated at any time
stored at 1-6C for up to 5 days after exp of WB
used as volume expander
which factors are reduced in cryo poor plasma?
- Factor VIII
- vWF antigen
- vWF activity
- Factor XIII
which coag factors are found in normal amounts in cryo poor plasma?
- Factor V
- Factor I
- Factor VII
- Factor X
- Protein C
- Protein S
- plasma for manufacture
- processed into derivatives
- has no expiration date
- records kept indefinitely
How is Cryoprecipitated AHF prepared?
- FFP thawed to 1-6C
- Cold-insoluble protein collected by centrifugation
- Cryo poor plasma transferred to another bag
- Precipitate is resuspended in 15 mL plasma
- Frozen within 1 Hr of preparation
Cryo AHF from which blood groups has higher leves of Factor VIII?
- From blood groups A and B
- 120 Vs. 80 IU (Group O)
How are granulocytes prepared from WB?
- 60 mL of hydroxyethyl starch (HES) is added to WB that are <24Hrs old
- Allowed to rest 1 Hr
- Gravitational force settles RBCs
- plasma and buffy coat transferred out
- plasma is centrifuged at 5000 x g for 50mins at 22C
- 90% of plasma transferred back to RBC bag
- 20mL of plasma is left with granulocytes
- typically collected by apheresis
- donors stimulated with corticosteroids
- necessary to transfuse before infectious disease testing is completed
What are the irradiation sources in use?
gamma rays from either cesium 137 or cobalt 60 sources
X-rays produced by radiation therapy linear accelerators or standalone units.
What should be the irradiaton dose to the center of the irradiation field?
at least 25 Gy (2500 cGy) and no more than 50 Gy (5000 cGy).
Besides dose mapping, what should also be monitored periodically for gamma irradiators?
- the turntable operation
- the timing device
- the lengthening of irradiation time caused by source decay
For gamma irradiators, how often should verification of delivered dose be performed?
What are the three methods used to measure hemoglobin?
- Copper-Sulfate density
- Spun microhematocrit
- Spectrophotometric measurament
Which clotting factor deficiency is not a cause for donor deferral?
Factor XII deficiency is not associated with bleeding or thrombosis. Persons with this deficiency could donate.
What are some of the desired properties of blood containers?
- pyrogen free
- flexible, tough, scratch resistant
- able to withstand sterilization
- allow adequate gas exchange
- prevent evaporation of H2O from component
- contains di-(2-ethylhexyl) phthalate (DEHP) to make it more pliable
when is leukocyte reduction done on RBCs?
- Usually within 72 Hrs
- Always within 120 Hrs of collection
- Residual WBCs shouldn't exceed 5 x 106
what's the amount of platelets found in 1 unit?
WB--->5.5 x 1010
Apheresis---> 3.0 x 1011
When are single-donor platelets generally indicated?
patients unresponsive to random platelets due to HLA alloimmunization
to limit platelet exposure from multiple donors
which type of bags are commonly used for the high-glycerol RBC cryopreservation method?
polyolefin bags are less brittle at -80C
Why is the high glycerol method for RBC cryopreservation preferred over the low-glycerol method?
does not require liquid nitrogen
How soon after collection should the glycerol be added to cryopreserve RBCs?
within 6 days
What is the storage temperature and shelf life of cryopreserved RBCs?
-65C or colder
10 years expiration
What is the final solution in which deglycerolized RBCs are suspended?
- Dextrose provide nutrients and support posttransfusion RBC
- viablitity for 4 days
Rejuvenation solution is not approved for which RBCs?
- For RBCs preserved in:
Why are RBCs rejuvenated?
Storage of RBCs causes reduction in the intracellular levels of 2,3-diphosphoglycerate (2,3-DPG) and ATP
Which principles apply for "serial" plasma collection?
- Donors must give consent, and they must be observed closely during procedure.
- RBC loss must not exceed 25mL/week
- total protein and serum protein electrophoresis or quantitative immunoglobulins, should be within normal limits
- 48 Hrs should elapse between procedures
- No more than 2 in a 7day period
Which corticosteroids are normally used to stimulate granulocytes donors?
Oral prednisone 60mg (single or devided dose)
Oral dexamethasone 8 mg
what is hydroxyethyl starch (HES)?
- common sedimenting agent
- enhance granulocyte harvest by causing increased sedimentation of RBCs
- Can be detected in donors for a year
- colloid; acts as volume expander
- May cause headaches or peripheral edema because of expanded circulatory volume
For which infectious agents are there FDA-licensed confirmatory assays?
In which circumstance, can a repeatedly reactive unit be used?
The syphilis screening assay (RPR) is the only situation in which negative supplemental test results, can permit use of a reactive unit.
Why is ID-NAT recommended for screening of WNV?
- viral RNA is often low in WNV infection
- when donor samples are combined into minipools (MP-NAT), sample may become diluted below detectable level
Which infectious agent, may be limited to one-time testing of each donor?
T. cruzi antibody (Chagas)
Refusal of autologous units with positive test results, may be interpreted as:
A violation of the Americans with Disabilities Act
There are no screening tests for which infectious agents?
variant Creutzfeldt-Jakob disease (vCJD)
With NAT, what is the window period of HIV?
With NAT, what is the window period of Hepatitis C?
What is the window period of Hepatitis B?
What was the first retrovirus identified?
- HTLV-1 was identified in 1978
- Isolated from a cutaneous T-cell lymphoma patient
What is a major cause of transfusion-related fatalities?
- Bacterial contamination of blood components
- Mainly platelets
What is the process most commonly used to screen platelets for bacteria?
BacT/ALERT culture system
Which supplemental test for T. cruzi is very helpful?
Radioimmunoprecipitation assay (RIPA)
What is the most common Babesia species and what is the vector?
vector is Ixodes scapularis (same tick that causes Lyme disease)
Syphillis is caused by which spirochete bacterium?
What are the 4 Plasmodium species that account for most malaria infections in humans?
- P. falciparum
- P. vivax
- P. malariae
- P. ovale
What are prions?
an infectious agent composed of protein in a misfolded form.
cause fatal infections of the nervous system called transmissible spongiform encephalopathies (TSEs)
CJD exclusions are for:
- family history of disease
- receipt of Pituitary derived human GH
- receipt of dura matter tissue graft
vCJD exclusions are for:
- residence in the UK or Europe for specified times when mad cow disease was endemic
- receipt of transfusion in UK or France
- receipt of UK bovine insulin
What is Pathogen Reduction Technology?
Processes that reduce the infectivity of residual pathogens in blood components
could reduce transmission of agents for which there are no donor screening tests
further reduce the residual transmission risk of known agents
Not approved in the US
What are some methods used in Pathogen Reduction Technology?
- prolonged heat
- solvent/detergent treatment
- cold ethanol fractionation
What are some potentital problems in intraoperative blood salvage?
air or amniotic fluid embolus risk
hemolysis of processed blood from excessive suction in the operative field
Coagulation factor activation
What are some advantages of acute normovolemic hemodilution (ANH)?
less hemoglobin loss
decreased blood viscosity increases cardiac output and may improve oxygenation
Coag factors and Platelets survive well for short periods and help hemostasis
DIC is associated with which autologous blood collection method?
Shed blood has undergone coagulation, fibrinolysis and hemolysis