CLINICAL LAB SCIENEC

CHAPTER 17: IMMUNOHEMATOLOGY (BLOOD BANKING) 421
3. Fill a 13 × 100 mm test tube with 0.85% normal saline from the squeeze bottle
for each blood sample for which a cell suspension is needed. Use this supply
of saline as the source of the appropriate drops of saline for the two levels of
suspension.
4. Label one of the 12 × 75 mm test tubes as 2% and one as 5%. The two separate
concentrations are prepared to ensure an adequate number of red blood cells
are available for testing in patients who may be anemic (low RBC count).
5. Using Pasteur or transfer pipettes, prepare 2% and 5% standard RBC suspensions
in the labeled tubes as shown below. These suspensions are an approximation
and an exact percentage is not critical.
2% Cell Suspension 5% Cell Suspension
Drops of Saline 98 95
Drops of RBCs 2 5
6. Cover each tube with Parafilm and invert gently to mix.
7. Compare the color intensity in the two prepared suspensions (2 and 5%) with that
of the screening cells. Note that one of the two should approximate the color
intensity of the commercially prepared screening cells. If the prepared 2% RBC
suspension is lighter in color intensity than those of the screening cells, then the
5% RBC suspension should be used for testing. The screening cells are used in
blood banking procedures to determine the presence of atypical antibodies in the
patient, or to confirm that the blood banking reagents used to test the cells in the
prepared suspensions are working correctly.
8. It is important that the technical personnel in a blood bank be able to quickly prepare
and approximate cell suspension of 2% and 5% red blood cells. With experience,
the blood bank professional can achieve the proper suspension without
using prepared standards. The student should practice preparing a 2% and a
5% cell suspension in the 12 × 75 test tubes as follows:
a. Put 1 drop of the RBCs in each tube.
b. Using the squeeze bottle, add sufficient saline to achieve a 2% to 5% cell
suspension in each of the five tubes.
c. Compare the color intensity of your suspensions to the standard 2% and
5% suspensions prepared from the table above. They should be roughly the
same.
d. With practice, the student can make approximate 2 or 5% solutions by adding
sufficient saline until the color intensity is approximately that of the standard
2 or 5% cell suspensions prepared by counting drops of RBCs and saline.
e. Repeat the procedure if the standard and the approximate preparations are
not close in concentration.
9. Discard all supplies used for the procedure in the appropriate containers. A disinfectant
should be used to clean the work surfaces and equipment should be
cleaned and restored to its former position. Gloves should be discarded appropriately
and the hands washed thoroughly in accordance with established policies.
Copyright 2010 Cengage Learning. All Rights Reserved. May not be copied, scanned, or duplicated, in whole or in part. Due to electronic rights, some third party content may be suppressed from the eBook and/or eChapter(s).
Editorial review has deemed that any suppressed content does not materially affect the overall learning experience. Cengage Learning reserves the right to remove additional content at any time if subsequent rights restrictions require it.