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Selecting the right test for the right patient is crucial in managing coagulation and hemostatic disorders. Speakers at two scientific sessions sponsored by AACC’s Hematology and Coagulation Division seek to drive home this point at the 71st AACC Annual Scientific Meeting & Clinical Lab Expo in Anaheim, California.

The Devil is in the Details: Coagulation Testing for Different Patient Populations (34221) will equip attendees with the tools to successfully and confidently run testing in their laboratories, discuss the results with clinicians and other providers, and understand caveats that arise, session moderator and presenter Anna Merrill, PhD, DBACC, assistant professor of pathology at the University of Iowa Hospitals & Clinics, told CLN Stat.

Significant therapeutic advances for both hemophilia and thrombosis have taken place, including emicizumab and direct oral anticoagulants, respectively. Such novel therapies, however, can interfere with routine and specialized coagulation tests. “Clinicians are not always aware of the impact these medications may have on test results, which puts patients at risk for mismanagement,” Merrill explained.

Interpreting coagulation testing without a proper analytical and clinical foundation is a challenge. Delving into this issue, Merrill and her two co-presenters will discuss coagulation testing and interpretation among three patient populations for which clinical laboratories often perform testing. Merrill’s talk will center on patients with liver disease. Meanwhile, Lindsay Bazydlo, BS, PhD, associate clinical professor of pathology at the University of Virginia Health System, will focus on patients taking direct oral anticoagulants, and Olajumoke Oladipo, MD, DABCC, FADLM, a pathologist with Penn State Milton S. Hershey Medical Center, will round out the session with a discussion on patients with autoimmune disorders.

The big take-home message: Interpreting coagulation tests is not a one-size-fits-all proposition, Merrill said. “Proper interpretation of even routine coagulation tests requires customization based on clinical information.” The Devil is in the Details: Coagulation Testing for Different Patient Populations will take place  August 7 from 2:30 p.m. to 5 p.m. and is worth 2.5 ACCENT credit hours.

Hemostatic Disorders That Can Kill You (35106) aims to familiarize labs with heparin-induced thrombocytopenia (HIT) and antiphospholipid syndrome (APLS), two life-threatening thrombotic disorders. William Winter, MD, DABCC, FADLM, professor of pathology and pediatrics at the University of Florida Diabetes Institute, and Neil Harris, MBChB, MD, clinical associate professor of pathology at the University of Florida, will be addressing the topics of APLS and HIT, respectively.

APLS has the potential to present a confusing array of paradoxical testing results, Harris told CLN Stat. “Traditional coagulation tests such as the APTT may be prolonged (suggesting a bleeding disorder) in the setting of thrombosis. Laboratory diagnosis of the APLS typically requires a battery of tests, many of which may be negative,” he said.

In the meantime, HIT tests used by many diagnostic laboratories show a low specificity—meaning that they yield positive results in patients who do not have this condition, Harris said.

Proper patient selection for testing is the key to diagnosing APLS and HIT. “This can reduce the likely of a positive but clinically insignificant lab test result,” Winter said. “For example, HIT autoantibodies should not be sought unless the patient is clinically suspected of having HIT.” Another issue is proper test selection, he said. Clinicians who suspect APLS have at their disposal a variety of tests, but few of these tests are actually recommended, he emphasized.

A targeted approach that involves a select combination of a few tests may prove more useful than a “shotgun” battery of coagulation testing in identifying these disorders. The latter approach “can lead to an incorrect diagnosis and management plan. For example, factor activity analysis in patients with APLS may be mistaken for factor VIII deficiency,” Harris said.

Attendees are expected to take away the following points:

  • Thrombotic conditions may cause irreversible damage or death;
  • The final diagnosis depends on careful assessment of a patient’s  clinical condition (“the pretest probability”) together with his or her laboratory results;
  • Awareness of the sensitivity and specificity of the tests is vital; and
  • Awareness of drug interactions with the testing is also important.

Worth 1.5 ACCENT credit hours, Hemostatic Disorders That Can Kill You will take place August 8 from 10:30 a.m. to noon.

Learn more about optimal testing strategies for these bleeding disorders at the 71st AACC Annual Scientific Meeting & Clinical Lab Expo.