TY - JOUR
T1 - Reducing the effect of DOAC interference in laboratory testing for factor VIII and factor IX
T2 - A comparative study using DOAC Stop and andexanet alfa to neutralize rivaroxaban effects
AU - Favaloro, Emmanuel J
AU - Gilmore, Grace
AU - Bonar, Roslyn
AU - Dean, Elysse
AU - Arunachalam, Sandya
AU - Mohammed, Soma
AU - Baker, Ross
N1 - © 2020 John Wiley & Sons Ltd.
PY - 2020/3
Y1 - 2020/3
N2 - INTRODUCTION: Investigation of factors (F) VIII and IX is common, with testing important for diagnosis or exclusion of haemophilia A or B, associated acquired conditions and factor inhibitors. Rivaroxaban, a common direct anti-Xa agent, causes significant interference in clotting assays, including substantial false reduction of factor levels.AIM: To assess whether rivaroxaban-induced interference of FVIII and FIX testing could be neutralized.MATERIALS AND METHODS: An international, cross-laboratory exercise for FVIII (n = 84) and FIX (n = 74), using four samples: (A) pool of normal plasma; (B) pool spiked with rivaroxaban (200 ng/mL); (C) rivaroxaban sample subsequently treated with 'DOAC Stop' and; (D) rivaroxaban sample treated with andexanet alfa (200 μg/mL). Testing performed blind to sample type.RESULTS: All laboratories reported normal FIX and 94% reported normal FVIII in the pool sample. Instead, 55% and 95%, respectively, reported abnormal FIX and FVIII levels for the rivaroxaban sample. DOAC Stop treatment evidenced a correction in most laboratories (100% reported normal FIX and 86% normal FVIII). Andexanet alfa provided intermediate results, with many laboratories still reporting abnormal results (59% for FVIII, 18% for FIX). We also identified reagent-specific issues.CONCLUSIONS: As expected, rivaroxaban caused false low values of FVIII and FIX. This might lead to increased testing to identify the cause of low factor levels and potentially lead to false identification of (mild) haemophilia A or B if unrecognized by clinicians/laboratories. DOAC Stop effectively neutralized the rivaroxaban effect, but andexanet alfa less so, with reagent-related effects evident, and thus, false low values sometimes persisted.
AB - INTRODUCTION: Investigation of factors (F) VIII and IX is common, with testing important for diagnosis or exclusion of haemophilia A or B, associated acquired conditions and factor inhibitors. Rivaroxaban, a common direct anti-Xa agent, causes significant interference in clotting assays, including substantial false reduction of factor levels.AIM: To assess whether rivaroxaban-induced interference of FVIII and FIX testing could be neutralized.MATERIALS AND METHODS: An international, cross-laboratory exercise for FVIII (n = 84) and FIX (n = 74), using four samples: (A) pool of normal plasma; (B) pool spiked with rivaroxaban (200 ng/mL); (C) rivaroxaban sample subsequently treated with 'DOAC Stop' and; (D) rivaroxaban sample treated with andexanet alfa (200 μg/mL). Testing performed blind to sample type.RESULTS: All laboratories reported normal FIX and 94% reported normal FVIII in the pool sample. Instead, 55% and 95%, respectively, reported abnormal FIX and FVIII levels for the rivaroxaban sample. DOAC Stop treatment evidenced a correction in most laboratories (100% reported normal FIX and 86% normal FVIII). Andexanet alfa provided intermediate results, with many laboratories still reporting abnormal results (59% for FVIII, 18% for FIX). We also identified reagent-specific issues.CONCLUSIONS: As expected, rivaroxaban caused false low values of FVIII and FIX. This might lead to increased testing to identify the cause of low factor levels and potentially lead to false identification of (mild) haemophilia A or B if unrecognized by clinicians/laboratories. DOAC Stop effectively neutralized the rivaroxaban effect, but andexanet alfa less so, with reagent-related effects evident, and thus, false low values sometimes persisted.
KW - Blood Coagulation Tests/methods
KW - Factor IX/pharmacology
KW - Factor VIII/pharmacology
KW - Hemostatics/pharmacology
KW - Humans
KW - Rivaroxaban/pharmacology
KW - Andexanet alfa
KW - DOAC Stop
KW - Interference
KW - Haemophilia
U2 - 10.1111/hae.13930
DO - 10.1111/hae.13930
M3 - Article
C2 - 31962376
SN - 1365-2516
VL - 26
SP - 354
EP - 362
JO - Haemophilia
JF - Haemophilia
IS - 2
ER -