Letting Go of the Rules of Three… and How Not to Let the MCHC Rule Your Life

12:00 PM to 1:00PM (Americas) Central Time (US & Canada)

Jeri Walters, SH(ASCP), Technical Supervisor Esoteric Testing, WI Core Lab, ACL Laboratories, West Allis, WI

The rules of 3 have been a staple in hematology for decades. This presentation will review the history of the rules of 3 and discuss why they were introduced into lab hematology – and why they need to go away. We will examine how modern sheath flow-based hematology analyzers have made the rules of 3 obsolete and why the RBC indices are much better indicators of problem samples. Learn what may cause abnormal and improbable indices and what to do about it.


  • Discuss the history of the rules of 3 and their original purpose in hematology testing
  • Explain the importance of the RBC indices and how they are better indicators of problem samples
  • Apply your knowledge of what can cause ‘spurious’ indices and identify alternate methods to resolve the problem
We regret the CEU credits for this webinar are no longer available.The American Society for Clinical Laboratory science(ASCLS) does not accept credits under the PACE program beyond 3 years. If you need additional assistance, please contact us at communications@sysmex.com
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