What do you do if you receive a sample in a TM lab that doesn’t fulfil the labelling requirements?
- must NOT be accepted -> recollect
- request must have ≥3 unique Identifiers
- identifiers on request form & tube must match
Summarise the ABO/Rh grouping requirements for pre-transfusion testing.
- Must perform a Group & Screen (ABO group & Ab screen)
- GROUP: do FWD & RVS group
- Not require RVS group for infants <4months bc Aby from mum
- confirm ABO/RhD match (do confirmatory test if new patient)
why don’t we need to use Aby that detects DVI in prenatal & postnatal maternal specimens
bc little evidence DVI+ (Ag) sensitises mum
In the case of an ABO discrepancy, which RBCs do you issue for transfusion if they are required before the discrepancy can be resolved? *& case of preg. woman
O Rh(D) neg blood units * O neg & K neg cells for preg. woman = avoid HDNB
Explain why O cells are used for aby screening.
- not have A, B, A,B Ag
- Specific to detect Aby from RH or other blood groups
Explain why homozygous Jk, Fy, and Ss cells are required in aby screening and ID*
- consider zygosity of Jk, Fy and Ss due to dosage
- bc heterozygous expression = weak reaction (bc slightly less [ ] of that Ag)
- vs homozygous = strong expression
What testing is the TM lab required to perform on donor cells?
- Crossmatch by IS or IAT
- > IS: if patient has NO history of clin. sig Aby
- > IAT: if patient has history of clin. sig Aby
- blood chosen should be Ag neg to patient’s Aby
Females of childbearing potential should receive what blood units?
Match ABO & RhD and K
*If in emergency = O neg & K neg
If pateint has Aby NOT considered as clinically sig. (e.g._), [test] @ _ºC should be selected for transfusion & Ag [do/don’t] need to be Ag Neg
a) anti -A1, -P1, -Lea, -Leb, -Lea+b, -HI, autoanti-I (other cold agglutinants)
b) IAT @ 37ºC
c) don’t need to be Ag Neg
What RBC units should you select & what test if patient history has no (or doubtful) CLin sig Aby and NOT currently reactive by IAT @37ºC
- ABO compatible RBC w/out doing IAT
- OR select Ag neg cells
What is phenotyping, and when is it performed during pre-transfusion testing?
- Phenotyping: determine the expression (of RBC) - blood group
- used for paternal phenotypingto determine is the father is Rh(D) Pos or Neg (when mum is Rh(D) neg) bc determine if baby is Rh(D) pos or neg
Discuss the selection of plasma products for transfusion recipients.
- Same ABO group as patient
- Group AB universal plasma product
- Rh(D) neg recipients can receive RhD pos plasma
Order of group preference when choosing a plasma product for recipient that is O group. & plt product
plma : plts O :1st: O A :2nd: A (*express A2) B :3rd: B 4th: AB
Order of group preference when choosing a plasma product for recipient that is A group. & plt product
plma : plts
A :1st: A
AB :2nd: B or O(*lo titre Ab or Pooled)
B (low titre = low Aby) :3rd: AB
Order of group preference when choosing a plasma product for recipient that is B group. & plt product
plma : plts
B :1st: B
AB :2nd: A or O (*lo titre Ab or Pooled, A2)
A (low titre = low Aby) :3rd: AB
Order of group preference when choosing a plasma product for recipient that is AB group. & plt product
AB :1st: AB
A (low titre = low Aby) :2nd: A or B (lo titre Ab or Pooled)
B (low titre = low Aby) :3rd: O (lo titre Ab or Pooled)
Order of group preference when choosing a plasma product for recipient that is unknown group. & plt product
AB :1st: A or O (*lo titre Ab or Pooled, A2)
A (low titre = low Aby) :2nd:
Discuss the selection of platelet products for transfusion recipients.
- preferably match ABO/Rh as patient
- but Match ABO desirable > RhD
- If Rh(D) neg recipients receive RhD pos plts MUST be given RhD-Ig = minimise I.Sys making RhD Ab
In an emergency, are you required to complete pre-transfusion testing before issuing blood product?
Explain your answer.
- RBC: Transfuse O Neg blood (E- & K-) to give (while grouping current sample)
- plasma: give group AB (or Ab @ low titre)
- Plt: ABO may not need to match (but may need to give Ab?)
what instances should you reject a sample and ask for a re-collect?
- request not have ≥3 unique Identifiers
- identifiers on request form & tube don’t match
- haemolysed sample
Explain the scenarios where samples for TS testing are valid for 72 hours, and 7 days (and up to 3 months*)
- If patient not transfused or pregnant in past 3 months = sample is valid for 7 days from collection
- If patient has been transfused or preg. in past 3 months = sample is valid for 72 hours (3 days) from collection [bc inc. risk for amnestic response]
* patient not preg or transfused in at 3 months, and is having surgery
What is the shelf life of RBCs? Platelets? Why is the platelet shelf life shorter?
a) RBC stored @ 2-6ºC for max. 42 days
b) Plt stored @ 20-24ºC for 5 days (w/ gentle agitation)
c) bc stored @ room temp. = inc. risk of bacterial contamination
why do we use an anti-A,B Ab as well in FWD grouping for baby’s grouping?
bc better at detecting subgroups
reasons for a positive XM in 1) IS and 2) IAT
1) Neg Aby screen but incompatible XM
- recipient & donor are ABO incompatible
- recipient produce cold Aby (react @ RT)
- ABO subgroup
2) Neg Aby screen but incompatible IAT XM
- Donor has pos. DAT
- recipient has Aby to low incidence Ag
