SIP

Subject Title: BLOOD BANK
Topic: Blood banking processes

yep, I was attached to the Blood Bank Laboratory for the whole of 20 weeks. There are 4 stations in the lab, 1) Requisitor 2) Screener 3) Depatching & Crossmatch 4) Issuer. I learnt quite a number of things through observations and some hands-on under supervision. I was not allowed to handle patients' samples yet as results had to be very accurate or else the consequences of wrong results can lead to adverse transfusion reaction.

- Sorting out labels that are returned to the lab after transfusion
- Handling of blood products received from CTM
-> Scan 1) Unit no. 2) Expiry date 3) Product code 4) Blood type into the LIS to document all the stock that are received.
-> Store in refrigerator under pending ABO rechecks for blood units.
-> Store in freezer at -60 degrees celsius for FFP (Fresh Frozen Plasma)
- Retrieval of transfusion records from filing cabinet
- Preparation of ABO tubes for screening and recheck
- ABO recheck of blood units

Purpose: To ensure correct blood type in the blood pack, preventing errors
E.g: Recheck of O+ve blood group
Procedures:
1) Paste the donor blood ID sticker on the "rechecking of donor blood form". Tally the unit no. of the blood pack with the label to prevent errors. (Every blood pack comes with a label which is used to fill in the particulars of the patient, date of transfusion, then issue out together with the blood unit and return back to the lab after transfusion.)
2) Add 1 drop of Anti-AB into a test tube.
3) Add saline into another tube.
4) Remove a segment from the blood pack. Draw the blood sample using a pipette. Dilute the blood in saline.
5) Add 1 drop of blood to the tube containing Anti-AB.
6) Centrifuge for 15 seconds at 3000 rpm.
7) Check for agglutination, record results under "rechecking of donor blood form".

Results: Negative. As O red cells lack of A and B antigens, thus there is no agglutination present with mixed with Anti-AB.

Blood samples are sent to Blood Bank Laboratory for ABO/Rh grouping and cross-match.

Role of a requisitor
When the blood samples are received, tally the doctor's signature/name, patient's NRIC no. and name on the request form with the label on the tube.

- Check with the LIS if the patient requires T1 or T2.
T1- requires ABO/Rh grouping only

T2- requires ABO/Rh grouping & Ab screening (15th day from the last Ab screening or 4th day onwards from the last blood transfusion which is just after last Ab screening.

- Centrifuge the blood tubes to separate the red cells and the serum/plasma.
Serum- top portion of the clotted blood (red tube)
Plasma- top portion of EDTA blood (lavender tube)

- Place the tubes according to the last digit of the patient's NRIC no. in the specimen rack for the screener.

Role of screener
1) Set up controls and calibrations, do daily quality control of working reagents to ensure the accuracy of results for all tests. These reagents are quality controlled daily.

• ABO cells recheck with Anti-A, Anti-B, Anti-AB to ensure that the correct cells are in the respective bottles
  
• Rh-ve & Rh+ve recheck with Anti-D

• Test if the Anti-Human globulin (AHG) reagent is working properly with *check cells & saline
  
  *Check cells are pools of group O RBCs sensitised with IgG
  
  Positive control: 1 drop of check cells with AHG reagent
  Negative control: 1 drop of check cells with 2 drops with of saline
  
  Interpretation of results
  Positive: Agglutination of RBCs
  Negative: No agglutination of RBCs


• Panel (SPO) cells recheck (SI, SII, SIII)
  Using gel card technique
  
  
  - Add 50uL of SI, SII & SIII into each 3 different microtube respectively.
  -Add 25uL of positive control cells (serum diluted with saline which contains the respective Ab) into the first 3 microtubes. Add 25uL of negative control cells (with no Ab) into the last 3 microtubes.
  - Incubate for 15 minutes
  - Centrifuge at 3000rpm for 15 seconds.
  - The results should be like the photo shown below:

*with permission from supervisor

Test: Antibody screening (Microtyping card gel)
Purpose: Screen for clinically significant blood group red cell antibodies in the pretransfusion samples, thus able to select suitabe blood units that will not cause harm to the patient, preventing adverse transfusion reactions. E.g: If the patient has Anti-Mia in the serum/plasma, blood units with the absence of Mia antigens must be issued to prevent transfusion reaction.

We used the ID LISS/Coombs Gel technique instead of the tube method we used in school.
The ID-card "LISS/Coombs" is a antibody screening panel which consists of 6 microtubes containing polyspecific AHG within the gel matrix, Rh-hr, Duffy, Kidd, Lewis, MNS, P, Kell and Mia antigens.


Procedure:
Allow the test cell reagents & samples to reach room temperature before use.
1) Identify the appropriate microtubes of the ID-card "LISS/Coombs" with the patient's name.
2) Remove the aluminium foil as many microtubes as needed.
3) Pipette 50 uL of *SPO cells (SI, SII, SIII) to the appropriate microtubes
*SPO cells - Specific pooled O+ cells with C, e, N antigens, etc
4) Add 25uL of the patient's serum/plasma to each microtube.
5) Incubate the ID-card for 15 minutes in the ID-incubator at 37 degrees celsius.
6) Centrifuge the ID-card for 10 minutes in the ID-centrifuge.
7) Grade & record the results in appropriate worksheet.
8) Leave the gel card & corresponding worksheet for counterchecking by second medical technologist.

Positive results: If the patient's serum/plasma contains abnormal Ab specific to the antigens present in the SPO cells, it forms clumps with the panel cells, resulting in agglutination. Thus, it is unable to pass through the gel and gets trapped at the top portion of the tube. Strong +ve are seen as a line at the gel/fluid interface. Weaker +ve are seen distributed throughout the gel.

Positive samples will be sent to CTM for investigations using the antibody identification panel.

Negative results: If there's absence of abnormal Ab in the patient's serum/plasma, agglutination will not occur. Thus, the non-clump cells are able to pass through the gel and settle at the bottom of the tube. -ve are seen as a red cell button at the bottom of the tube.

*All results are counterchecked by second medical technologist for verification, ensuring accuracy of results & preventing analytical errors. (internal quality control)

Abbreviated crossmatch (Compatibilty testing)

Purpose: To test whether the donor's blood is compatible with the patient's serum, thus able to promote safe transfusion of blood and prevent transfusion reactions.

Procedures:
1) Take the requested blood unit from the refrigerator according to the patient's blood type.
2) Pull out a segment from the blood pack. Draw the blood sample using a pipette. Dilute the blood in saline.
3) Centrifuge at 3000rpm for 15 seconds to wash the cells.
4) Pour away the suspension into the waste bucket and add saline.
5) Add 3 drops of patient's serum into a tube.
6) Add 1 drop of the donor's blood into the same tube.
7) Centrifuge at 3000 rpm for 40 seconds.
8) Read the results under the microscope.

Positive results: Presence of agglutination
Negative results: Donor's RBC is compatible with the patient's (recipient's) serum/plasma, therefore able to proceed with the issuing of blood unit.

Crossmatch specimens are valid for 3 days from the day of receiving after which new specimens are required. (In case of disputes, for investigation & legal cases. The red cells may lyse after that period.) Samples are placed in the specimen racks according to the last digit of the patients' NRIC no. Day 1 samples are placed on the workbench at room temperature for easy retrieval during crossmatching. Day 2 & 3 samples are stored in the refrigerator. At end of day 3, they are bundled in yellow biohazard bags.

Some of the blood products that are issued by Blood Bank:

- Packed cells (without plasma & platelets)
Function: To raise the Hb level up faster as it's more concentrated with no plasma.
Life span: 45 days

- Whole blood
Function: To produce greater expansion of blood volume, especially for patients with massive blood loss
Life span: 36 days

- Platelets (random/apheresis)
Function: To prevent or to treat bleeding due to severely low platelet counts (thrombocytopenia)
Life span: 9 days

- FFP (Fresh Frozen Plasma) & cryoprecipitate
Function: For patients with abnormal or low levels of blood clotting proteins, such as hemophilia.
Life span: when frozen, can be kept for around 1 year. when thawed, had to be used within 24 hours.

- IvIg (Intravenous Gamma Globulin)
Function: To increase patient's immunity against infections

- Human albumin (5%/20%)
Function: For restoration and maintenance of circulating blood volume

- Factor VIII
Function: For treatment of acquired Factor VIII deficiency or hemophilia A

- Autologous blood

- Leco-reduced/ deglycerolysed RBC

Leco-reduced RBC: Where the leukocytes from red cells are filtered off or removed
Deglycerolised RBC: For patients who are sensitised with to IgA protein or to leukocyte or platelet antigens

- Washed cells (freezed with glycerol to preserve the cells)
They're used in cases of emergency when the stock is low. The cells are defrozen & washed to remove the preservatives. The disadvantage of washed cells is that their life span is very short.

yep, that's about it. Free free to ask any questions. I'll try my best to answer them all. Continue enjoy the rest of the SIP period! (: take care

Lastly, wanna share something.
my colleague told me this,
With skills comes good work.
With passion comes artistic work.
With passion & skills will produce a masterpiece.
yep, passion & skills are essential in excelling in your work. =)

Png En Hui Dorothy
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