Why do you need to prepare red cell suspension at 2-5%?
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cells to be tested removes serum or plasma which may contain proteins that interfere with testing, causing non-specific agglutination or rouleaux formation. Washing also removes fibrinogen, which may cause small clots.
The ratio of serum to cells markedly affects the sensitivity of agglutination tests. Preparation of a 2-5% cell suspension provides cells in an optimum concentration to detect weak antibodies.
REAGENTS, EQUIPMENT, AND SUPPLIES
Wash bottle with isotonic saline.
12 x 75 mm tubes.
Indelible marking pen.
Test tube rack
Dispo pipets.
Serofuge.
Dump bucket.
SAMPLE
Washed 3% suspensions may be made from clotted whole blood, from anticoagulated patient samples, or from donor blood taken from a sealed segment on the donor unit.
PROCEDURE
Using an indelible marking pen, label a 12 x 75 mm tube with the last name of the patient whose cells are to be washed, or with the last 3 digits of the donor number of the unit to be washed.
Using a dispo pipet, transfer 2-4 drops of blood from the sample to the labeled tube.
If a sample from a donor unit is to be washed, use a lancet or other device to make a small hole in one of the segments attached to the donor unit. Squeeze a drop of red cells into the appropriately labeled tube. Avoid using excess pressure or the cells will hemolyze.
Forcibly squirt saline from the wash bottle into the tube until it is about 3/4 full.
Centrifuge 45-60 seconds at high speed in the serofuge.
Decant into the dump bucket and shake to resuspend completely.
If gross hemolysis is present, repeat steps 3 to 5 until supernate is reasonably clear.
After the final wash, shake the tube to completely resuspend the cells and add saline to a final concentration of approximately 3%. Reagent test cells are in a 2-5% concentration. These can be used as a comparison.
NOTES AND PRECAUTIONS
To prevent contamination, do not touch tubes with the tip of the saline bottle.
Resuspend the cell button thoroughly between washes before adding more saline to ensure complete washing.
Do not attempt to mix a tube full of saline.
Do not mix cells by using your gloved finger as a stopper.
To prevent cells from spraying out during centrifugation, fill tubes no more than
The ratio of serum to cells markedly affects the sensitivity of agglutination tests. Preparation of a 2-5% cell suspension provides cells in an optimum concentration to detect weak antibodies.
REAGENTS, EQUIPMENT, AND SUPPLIES
Wash bottle with isotonic saline.
12 x 75 mm tubes.
Indelible marking pen.
Test tube rack
Dispo pipets.
Serofuge.
Dump bucket.
SAMPLE
Washed 3% suspensions may be made from clotted whole blood, from anticoagulated patient samples, or from donor blood taken from a sealed segment on the donor unit.
PROCEDURE
Using an indelible marking pen, label a 12 x 75 mm tube with the last name of the patient whose cells are to be washed, or with the last 3 digits of the donor number of the unit to be washed.
Using a dispo pipet, transfer 2-4 drops of blood from the sample to the labeled tube.
If a sample from a donor unit is to be washed, use a lancet or other device to make a small hole in one of the segments attached to the donor unit. Squeeze a drop of red cells into the appropriately labeled tube. Avoid using excess pressure or the cells will hemolyze.
Forcibly squirt saline from the wash bottle into the tube until it is about 3/4 full.
Centrifuge 45-60 seconds at high speed in the serofuge.
Decant into the dump bucket and shake to resuspend completely.
If gross hemolysis is present, repeat steps 3 to 5 until supernate is reasonably clear.
After the final wash, shake the tube to completely resuspend the cells and add saline to a final concentration of approximately 3%. Reagent test cells are in a 2-5% concentration. These can be used as a comparison.
NOTES AND PRECAUTIONS
To prevent contamination, do not touch tubes with the tip of the saline bottle.
Resuspend the cell button thoroughly between washes before adding more saline to ensure complete washing.
Do not attempt to mix a tube full of saline.
Do not mix cells by using your gloved finger as a stopper.
To prevent cells from spraying out during centrifugation, fill tubes no more than
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