PB0098 - Homogeneous Enzyme Immunoassay for the Direct Determination of Apixaban in Human Plasma

Sunday, June 23, 2024

13:45 – 14:45 ICT

Room: Exhibition Hall

Presenting Author(s)

RS

Rajendra Singh

Sr Director
ARK Diagnostics
Fremont, California, United States

Co-Author(s)

SO

Soon Oh

Sr Director R&D
ARK Diagnostics
Fremont, California, United States
JS

Jane Sheill

Scientist
ARK Diagnostics
Fremont, California, United States
KP

Khanhlinh Pham

Scientist
ARK Diagnostics
Fremont, California, United States
CP

Christina Pham-le

Scientist
ARK Diagnostics
Fremont, California, United States
KK

Kenneth Kasper

Consultant
ARK Diagnostics
Fremont, California, United States
TH

Thomas Houts

Sr Director
ARK Diagnostics
Fremont, California, United States
DL

Dionne Labatore

Director RA & QA
ARK Diagnostics
Fremont, California, United States
RO

Robert O'Malley

President ARK Diagnostics
ARK Diagnostics
Fremont, California, United States

Background: Direct oral anticoagulants (DOACs) are now the first line therapy alternatives to vitamin K
antagonists (VKAs) for prevention of blood clots and stroke in patients at risk of deep venous thrombosis,
atrial fibrillation, pulmonary embolism, and post-surgical clots. Time based and Factor Xa activity measurements are indirect measurements of DOACs prone to interferences.

Aims: Develop a homogeneous enzyme immunoassay to measure Apixaban (Eliquis) concentrations on automated clinical analyzers

Methods: The ARK Apixaban Assay utilizes a homogeneous enzyme immunoassay, consisting of two stable liquid reagents, 6 calibrators encompassing a broad dynamic range and 3 controls (10, 30 and 200 ng/mL). The performance of three lots of the ARK assay was evaluated on the Beckman AU680 Automated Clinical Chemistry Analyzers. Precision, limit of quantitation (LOQ), recovery, specificity and method comparison were studied

Results: Total 20-Day precision ranged from 4.3 to 7.3%CV, 2.2 to 4.3%CV, and 4.3 to 8.3%CV for lot 1, 2, and 3, respectively for the 3 quality controls and for 3 spiked plasma samples. Less than 5 % variability was observed among the 3 lots. LOQ was 3.0 ng/mL. One hundred thirty-five specimens at concentrations spanning 5.4 to 394 ng/mL were assayed and gave the following Passing Bablok regression results when compared to LC-MS/MS values: ARK = 0.97 LC-MS/MS + 1.58 (r2 = 0.95), ARK = 1.07 LC-MS/MS + 0.07 (r2 = 0.95), and ARK = 1.03 LC-MS/MS + 0.98 (r2 = 0.97) for lot 1, 2, and 3, respectively.

Conclusion(s): The ARK Apixaban Assay measures apixaban in human plasma with excellent precision at very low concentrations essential for emergency situations. The ability to directly measure trough levels of apixaban with high accuracy and fast turn-around time makes this method clinically useful for the determination of apixaban concentration in human plasma.