Type and Screen Testing: When to Repeat
Type and screen testing should not be repeated within 3 days of a previous test unless specific clinical indications exist, as it is valid for up to three calendar days according to the American Association of Blood Banks. 1
General Guidelines for Type and Screen Testing
- Type and screen (T&S) testing is a safe and effective preoperative blood ordering policy that includes ABO/Rh typing and screening for unexpected antibodies 2, 3
- The validity period for a T&S is up to three calendar days, after which a new sample should be collected 1
- Unnecessary repeat T&S testing within the 3-day validity period represents costly medical waste and can potentially lead to patient harm 1
Specific Indications for Repeating Type and Screen
- Repeat testing is warranted in cases of suspected transfusion reactions 1
- When a patient has a positive antibody screen result (which occurs in approximately 3.75% of cases), additional testing may be required 2
- In cases where "borderline" or "dubious" lupus anticoagulant results are obtained, repeat testing is recommended after 1 week 4
Benefits of Appropriate Type and Screen Testing Practices
- Implementation of proper T&S policies has been shown to reduce the crossmatch-to-transfusion ratio from 8.96 to 1.84 in obstetrical and gynecological practice 2
- Proper T&S protocols have demonstrated 99.99% effectiveness in preventing the transfusion of incompatible blood 5
- Reducing duplicate T&S testing through electronic health record interventions has achieved significant reductions (up to 48.7%) in unnecessary repeat testing 1
Special Considerations
- For patients with lupus anticoagulant testing, if results are inconclusive, repeat testing should be performed after 1 week rather than immediately 4
- In patients with suspected fetal and neonatal alloimmune thrombocytopenia, delayed alloantibodies may appear several weeks after birth, requiring repeat testing 2-8 weeks later 4
- False-negative results in antibody testing can occur due to delayed appearance of antibodies, suggesting the value of repeat testing in specific clinical scenarios 4, 6
Implementation Strategies to Reduce Unnecessary Testing
- Adding information about the time elapsed since the last T&S order into the ordering process can reduce duplicate testing by 12.5% 1
- Implementing best practice advisories that trigger when T&S is ordered before the expiration of an active T&S can further reduce duplicate testing by an additional 48.7% 1
- Proper T&S policies can lead to significant cost savings while maintaining patient safety 3
By following these guidelines, healthcare facilities can ensure appropriate use of T&S testing, reducing unnecessary repeat testing while maintaining patient safety and efficient resource utilization.