The Pre-Operative Type and Screen: Why Timing is Everything!

Sarah Barnhard MD, Associate Medical Director of Transfusion Services
Brandon Thomas CLS, MT(ASCP), Transfusion Services Supervisor
David Unold MD, Transfusion Services Faculty
Grace Monis MD/PhD, Medical Director of Therapeutic Apheresis
Hanne Jensen MD, Medical Director of Transfusion Services

Background

The clinical laboratory is one of the most highly regulated services in the hospital, and transfusion services is one of the most highly regulated areas in the lab! The FDA’s Center for Biologics Evaluation and Research (CBER) regulates biological products for human use under applicable federal laws1. The AABB sets standards for transfusion medicine2 and these are incorporated as state law in California3. Other organizations such as the College of American Pathology also set standards for our laboratory’s accreditation4. All this oversight ensures our laboratory’s processes and protocols produce accurate results.

Pre-transfusion testing requirements are delineated by all regulatory, accreditation, and standards organizations. Pre-transfusion testing is incredibly important, because for each transfusion given within UC-Davis Health (over 20,000 RBC units in 2017!) this testing ensures the donor blood is compatible with the recipient.

The “type and screen” (T&S) is the first step in determining donor/recipient compatibility. Even though it is one order and one blood draw, it is 3 different tests. The T&S determines the ABO blood type of the patient, determines the Rh blood type of the patient (specifically, whether the D antigen in the Rh blood group is present or not), and screens the patient for any non-ABO antibodies that may have developed against donor red blood cells.

The blood supplier tests the ABO blood type, the Rh blood type, and the non-ABO antibody screen for all blood donors too5. UCDMC’s transfusion services laboratory even confirms blood donor testing!

Does all of this fulfill the regulatory requirements for pre-transfusion testing? Partially. The type and screen must also be drawn at the right time. AABB’s standards state6:

5.14 Pre-transfusion tests for allogeneic transfusion shall include ABO group and Rh type. In      addition, for whole blood, red blood cells and granulocyte components, pretransfusion testing for unexpected antibodies to red cell antigens shall be performed.

5.14.3.1 When clinically significant antibodies are detected additional testing shall be performed.

5.14.3.2 A sample shall be obtained from the patient within 3 days of the scheduled transfusion in the following situations.

1) If the patient has been transfused in the preceding 3 months with blood or a blood component containing allogeneic red cells.

2) If the patient has been pregnant within the preceding 3 months.

3) If the history is uncertain or unavailable.

Lab Best Practice

So how do we translate these regulatory requirements into best practices for patients being scheduled for elective surgery?

The patient should be evaluated for their risk of needing blood transfusions. The maximum surgical blood order schedule (MSBOS) is used to determine general risk based on the procedure7. Patients with a >5% probability of transfusion based on procedure type are considered of sufficient risk to prepare for a possible transfusion8. Pre-op clinical evaluation is prudent to assess for co-morbidities that impact this risk stratification as well.

For patients undergoing applicable elective procedures, a type and screen should be drawn within 30 days of the scheduled procedure. This initial T&S allows transfusion services to fulfill AABB standard 5.14.3.1 – When clinically significant antibodies are detected, additional testing shall be performed. Epidemiologic studies reveal that 1-3% of the general patient population will have a non-ABO red blood cell antibody9. After a positive antibody screen is detected, the additional testing (antibody identification and finding/crossmatching the compatible blood) takes several hours or sometimes several days to complete. It is impractical to expect this testing to be done emergently the day of surgery. Massive transfusion ‘universal blood’ is also not guaranteed safe to provide when the antibody screen is positive since it may be incompatible.

Since it is logistically challenging to confirm history in most cases, UCDMC’s hospital transfusion policy requires a type and screen to be drawn from every patient within 3 days of their scheduled transfusion whether they have a history of transfusion/pregnancy or not10. A second T&S should therefore be drawn within 3 days of surgery. Any products ordered for surgery will be crossmatched using this fresh sample.

Conclusion

Appropriate pre-op planning ensures blood availability for the date/time of surgery and reduces the risk of a canceled procedure. Following this lab best practice helps to certify the right blood gets to the right patient at the right time. It reduces the risk of adverse events or canceled procedures and improves system efficiency. It’s a win/win for everyone, most importantly for our patients.

References:

  1. Information online at https://www.fda.gov/BiologicsBloodVaccines/default.htm. Accessed 9/11/18.
  2. Information online at http://www.aabb.org/tm/Pages/default.aspx. Accessed 9/11/18.
  3. Information online at https://www.cdph.ca.gov/Programs/OSPHLD/LFS/Pages/BloodBanksandBiologics.aspx. Accessed 9/11/18.
  4. Information online at http://www.cap.org/web/home/lab/accreditation/laboratory-accreditation-program. Accessed 9/11/18.
  5. Information online at https://www.redcrossblood.org/biomedical-services/blood-diagnostic-testing/blood-testing.html. Accessed 9/11/18.
  6. Standards for Blood Banks and Transfusion Services 31st Effective April 1, 2018. AABB Press.
  7. On the intranet at http://intranet.ucdmc.ucdavis.edu/pacu/Transfusion%20Blood%20Bank/MSBOS.pdf. Accessed 9/11/18.
  8. Frank, SM et al. Reducing Unnecessary Preoperative Blood Orders and Costs by Implementing an Updated Institution-Specific MSBOS and a Remote Electronic Blood Release System. Anesthesiology. 2014 Sep; 121(3): 501–509.
  9. Zhengtong P and Arpad S. Prevention of surgical delays by pre-admission type and screen in patients with scheduled surgical procedures: improved efficiency. Blood Transfus. 2015 Apr; 13(2): 310-312.
  10. On the intranet at http://intranet.ucdmc.ucdavis.edu/policies/patient_care_standards/line_management_therapy/xiii-12.shtml. Accessed 9/11/18.
By | 2018-09-14T07:57:05+00:00 September 15, 2018|0 Comments

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