BLOOD BANKING
CLINICAL ROTATION
Done by: Zaynab Alabbad
2017200031
Blood donation
Blood Donation Process
Donating blood is a safe, simple, and rewarding experience that
usually only takes 45-60 minutes.
Before You Donate
To donate blood, find a blood bank near you using AABB’s blood bank
locator. Then, call the blood bank to make an appointment. When
making the appointment, ask the following questions:
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What are your general donor requirements? (Most places
require you to weigh a minimum of 110 pounds, be at least 16
years old and be generally healthy).
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What kind of identification is required? (First-time donors are
usually asked to present two forms of identification—the type of
identification needed varies by facility).
If you have any particular health concerns or have traveled
outside of the country, it’s also a good idea to inform the blood
bank at the time you are making your appointment.
When You Arrive at the Blood Donation Center
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When you sign in, you will be asked to complete a donor
registration form, which includes your name, address, phone
number, and various other types of demographic information.
You will also be asked to show your donor card or the type of
identification required by the particular blood bank you visit.
Pre-Donation Screening
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During pre-donation screening, a blood bank employee will ask
you some questions about your health, lifestyle, and disease risk
factors. All of this information is confidential.
Next, an employee will perform a short health exam, taking your
pulse, temperature and blood pressure.
A drop of blood from your finger will also be tested to ensure
that your blood iron level is sufficient for you to donate. All
medical equipment used for this test, as well as during the
donation process, is sterile, used only once and then disposed.
Blood Donation
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Once the pre-donation screening is finished, you will proceed to
a donor bed where your arm will be cleaned with an antiseptic,
and a professional will use a blood donation kit to draw blood
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from a vein in your arm. If you are allergic to iodine, be sure to
tell the phlebotomist at this point.
During the donation process, you will donate one unit of blood;
this takes about six to ten minutes.
Post-Donation
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Following your donation, you will receive refreshments in the
canteen area, where you can stay until you feel strong enough to
leave.
After donating, it is recommended that you increase your fluid
intake for the next 24 to 48 hours; avoid strenuous physical
exertion, heavy lifting or pulling with the donation arm for about
five hours; and eat well balanced meals for the next 24 hours.
After donating, smoking and alcohol consumption is not
recommended
Although donors seldom experience discomfort after donating, if
you feel light-headed, lie down until the feeling passes. If some
bleeding occurs after removal of the bandage, apply pressure to
the site and raise your arm for three to five minutes. If bruising
or bleeding appears under the skin, apply a cold pack
periodically to the bruised area during the first 24 hours, then
warm, moist heat intermittently.
If you have any questions concerning your donation or
experience any unexpected problems, please call the center
where you donated blood.
Blood Typing
Blood typing is a test that determines a person’s blood type. The test
is essential if you need a blood transfusion or are planning to donate
blood. Not all blood types are compatible, so it’s important to know
your blood group. Receiving blood that’s incompatible with your
blood type could trigger a dangerous immune response.
Why blood typing is done
Blood typing is done prior to a blood transfusion or when classifying a
person’s blood for donation. Blood typing is a fast and easy way to
ensure that you receive the right kind of blood during surgery or after
an injury. If you’re given incompatible blood, it can lead to blood
clumping, or agglutination, which can be fatal.
Blood typing is especially important for pregnant women. If the
mother is Rh-negative and the father is Rh-positive, the child will
likely be Rh-positive. In these cases, the mother needs to receive a
drug called RhoGAM. This drug will keep her body from forming
antibodies that may attack the baby’s blood cells if their blood
becomes mixed, which often happens during pregnancy.
How blood typing is performed
The blood draw can be performed at a hospital or a clinical
laboratory. Your skin will be cleaned before the test with an antiseptic
to help prevent infection. A nurse or technician will wrap a band
around your arm to make your veins more visible. They will use a
needle to draw several samples of blood from your arm or hand. After
the draw, gauze and a bandage will be placed over the puncture site.
In order to determine your blood type, a lab technician will mix your
blood sample with antibodies that attack types A and B blood to see
how it reacts. If your blood cells clump together when mixed with
antibodies against type A blood, for example, you have type B blood.
Your blood sample will then be mixed with an anti-Rh serum. If your
blood cells clump together in response to the anti-Rh serum, it means
that you have Rh-positive blood.
After blood typing
Your blood type can be determined in a matter of minutes. Once you
know your blood type, you can donate blood and receive transfusions
from donors in the compatible blood groups.
Cross-Matching
Cross Matching is a procedure performed prior to a blood transfusion
to determine whether donor blood is compatible (or incompatible)
with recipient blood. Compatibility is determined through matching of
different blood group systems, the most important of which are the
ABO and Rh system, and/or by directly testing for the presence of
antibodies against a sample of donor tissues or blood.
Purpose of cross matching
The crossmatch is routinely used as the final step of pretransfusion
compatibility testing. The purposes of compatibility testing are to
detect: irregular antibodies; errors in ABO grouping, and clerical
errors in patient identification and result recording. The crossmatch
will detect the following:
1. Most recipient antibodies directed against antigens on the donor
red blood cells.
2. Major errors in ABO grouping, labeling, and identification of donors
and recipients.
Principle
Cross-matching will detect incompatibilities between the donor and
recipient that will not be evident on blood typing. There are two types
of cross-matches: Major cross-match and Minor cross-match.
The major crossmatch involves testing the patient’s serum with donor
cells to determine whether the patient has an antibody which may
cause a hemolytic transfusion reaction or decreased cell survival of
donor cells. This is the most important cross-match.
The minor crossmatch involves testing the patients cells with donor
plasma to determine whether there is an antibody in the donor’s
plasma directed against an antigen on the patient’s cells.
Procedure
1. Prepare donor and recipient blood samples:
For Major crossmatch : Donor’s red cell and recipient serum or plasma
For Minor crossmatch : Recipient red cells and donor’s serum or
plasma
2. Prepare 3 – 5% cell suspensions of red cells.
3. Major Crossmatch:
Label a test tube. Add two drops of the patient serum and one drop of
the appropriate donor cell suspension.
4. Minor Crossmatch:
Label a test tube. Add two drops of the appropriate donor serum and
one drop of the patient cell suspension.
5. Mix the tubes and incubate at 37°C for about 45 minutes.
6. Add two drops of AHG (Antihuman globulin) and mix well.
7. Centrifuge for 1 minute at 1500 rpm
8. Read macroscopically and microscopically and record the results
Direct Antiglobulin Test
Also Known As: DAT, Direct Coombs Test, Direct Anti-human Globulin Test
Why Get Tested?
To help diagnose the cause of red blood cells destruction (hemolytic
anemia); to investigate a blood transfusion reaction; to
diagnose hemolytic disease of the newborn
When To Get Tested?
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When you have had a blood transfusion recently and are
experiencing symptoms of a transfusion reaction, such as
dizziness, back pain, dark urine, shortness of breath
When a newborn shows signs of hemolytic disease of the
newborn
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When you have symptoms of increased destruction of your red
blood cells, which may include feeling tired more often than
usual, shortness of breath, headaches, paleness and your
healthcare practitioner wants to find out if this happens because
your immune system mistakenly makes antibodies that destroy
your red blood cells
Principle
The Direct Antiglobulin Test detects in vivo coating of patient cells either IgG antibodies, complement, or both. Within the patient's
blood stream antibodies attach to their specific antigens on the red
blood cells. This happens in Hemolytic Disease of the Newborn
(HDN), in transfusion reactions, and in autoimmune hemolytic
anemia. Certain drugs are also known to activate complement and it
can also coat the cells in vivo.
When the blood is drawn the antibodies and/or complement have
already attached to the red cells. Those red cells from the EDTA tube
will be washed 3 or more times and a 3% cell suspension is made. A
drop of cell suspension and the anti-human globulin are mixed in a
tube and then centrifuged. If agglutination occurs, it indicates the
patient has a positive Direct Antiglobulin Test due to antibody coating
the cells in vivo. If IgM antibodies involved, DAT will be identified by
complement binding since the polyspecific antisera has both anti-IgG
and anti-C3. The meaning of a positive DAT is found under Clinical
Causes of a Positive DAT.
Technique
Add 1 drop of patient cells from EDTA tube to tube
Wash these drops of blood 3-4X to remove plasma antibodies and
make a 3% cell suspension.
Add a drop of 3% cell suspension to a clean, labeled tube.
Add drop of Polyspecific AHG (Coombs serum) to the tube.
If test is positive with polyspecific reagent, set up again using
monospecific reagents to see if it is antibody or complement or both
coating the cells.
We want to make the test as sensitive as possible, so allow all
negatives to incubate 5 minutes to enhance complement coating.
Read all negatives microscopically to detect weak coating.
False pos. possible if red top tube used to collect sample.
In-vitro complement coating frequently happens when sample clots or
cools down due to weak cold-acting auto-antibodies like anti-I
Prevent by using lavender top tube to tie up Ca+ and Mg+ ions and
prevent complement activation in vitro.
Whenever positive DAT is obtained, obtain the following information
on the patient:
Diagnosis (particularly autoimmune hemolytic anemia, hemolytic
disease of the newborn and transfusion reactions)
Medications
Recent transfusion history of both red cell and plasma components
Other lab values that may indicate red cell destruction (hematocrit,
bilirubin, LDH)