ABO forward typing Flashcards
testing with both anti-A and anti-B is necessary to?
determine if rbc possess or lack A and/or B blood group of antigens
absence of agglutination is a ___ which indicates ___
negative result
indicates the corresponding antigen is not demonstrable.
agglutination of rbc with a given reagent is a ___ which indicates ___
positive
indicates presence of corresponding antigen on the red test result, which indicates the presence of the corresponding antigen on the rbc
materials needed in abo typing tube method
- gloves
- 5 ml test tubes
- test tube rack
- calibrated plastic pipets
- buffered nss
- antisera (A and B)
- serological centrifuge
- markers/gum labels
- biohazard container
- blood samples
quality control
- reagent must be tested daily
- do not use beyond expiration date
- store at 2C - 8C
preservative of the reagent
sodium azide 0.1%
storage temp when using the reagent
room temp (20-30C)
specimen of choice
EDTA anticoagulated blood
stroage req of blood samples
2-8C
make 3-5% rbc suspension by adding?
- 1 drop washed red cells
- 19 drops buffered NSS
color of anti-A
cobalt blue
how many drops of rbc suspension in A tube and B tube?
1 drop
after mixing the contents of the tube, what is the next thing to do?
centrifuge all tubes for 30 secs
steps in tube method
- label test tubes
- make 3-5% rbc suspension
- place reagents on each appropriate tube
- add 1 drop rbc suspension
- mix content and centrifuge
- gently re-suspend the rbc button and examine them for agglutination
- read and record the result
positive test indicates?
agglutination of rbcs
presence of corresponding antigen
negative control should have?
a negative result
common sources of technical error in ABO typing (10)
- inadequate identification of blood specimens, test tubes or slides.
- cell suspension either too heavy or too light
- clerical errors
- a mix-up in samples
- missed observation of hemolysis
- failure to add reagents
- failure to follow manufacturer’s instructions
- uncalibrated centrifuge
- contaminated reagents/expired reagents
- warming during centrifugation due to uncalibrated centrifuge
several large agglutinates - clear background, what is the strength of reaction?
+3
appearance of +4
one solid agglutinate
tiny/small agglutinates - turbid background indicates strength of reaction ___
+1 to W+
+2 appearance
medium sized agglutinates - clear background
0 appearance in grading of agglutination
no agglutination or hemolysis
designed to check for the presence of the expected ABO blood group antibodies
reverse grouping
sample of choice of reverse
plasma can be used but serum is preferred
