We use cookies to understand how you use our site and to improve your experience. This includes personalizing content and advertising. To learn more, click here. By continuing to use our site, you accept our use of cookies. Cookie Policy.

Features Partner Sites Information LinkXpress hp
Sign In
Advertise with Us
ZeptoMetrix an Antylia scientific company

Download Mobile App




Drug Causes Missed Diagnosis of Protein S Deficiency

By LabMedica International staff writers
Posted on 01 Jan 2018
Print article
Image: The Star Evolution coagulation analyzer (Photo courtesy of Diagnostica Stago).
Image: The Star Evolution coagulation analyzer (Photo courtesy of Diagnostica Stago).
Rivaroxaban is a direct, antithrombin-independent factor Xa inhibitor, which inhibits not only free factor Xa, but also clot-bound factor Xa and the prothrombinase complex. It is used for treatment and prevention of venous thromboembolism, as well as for prophylaxis of stroke in patients with atrial fibrillation.

Many patients taking rivaroxaban undergo hypercoagulation testing to rule out common inherited or acquired causes of hypercoagulability, including assays for activated protein C resistance (APCR) to detect factor V Leiden (FVL), and tests for protein S deficiency. However, it has been reported that spiking normal plasma with rivaroxaban caused an artefactual increase in the APCR ratio.

Scientists at Massachusetts General Hospital (Boston, MA, USA) compared of 60 patients in four different groups: FVL heterozygous (FVL-HET)/taking rivaroxaban, wild-type/taking rivaroxaban, FVL-HET/no rivaroxaban, and normal APCR/no rivaroxaban, and 32 patients taking rivaroxaban were tested for protein S functional activity and free antigen.

The patients were evaluated using the standard FVL testing protocol: an activated partial thromboplastin time (aPTT)-based APCR assay with dilution in factor V–deficient plasma on a Star Evolution analyzer and an FVL DNA assay. Protein S functional activity was measured using the Stago STACLOT Protein S assay on a Star Evolution analyzer, and free protein S antigen was measured using the Stago Asserachrom Free Protein S.

The team found that the FVL-HET patients taking rivaroxaban had lower APCR ratios than wild-type patients. For FVL-HET patients taking rivaroxaban, mean APCR was 1.75 ± 0.12, versus 1.64 ± 0.3 in FVL-HET patients not taking rivaroxaban. Activated protein C resistance in FVL-HET patients fell well below the cutoff of 2.2 at which the laboratory reflexes FVL DNA testing. No cases of FVL were missed despite rivaroxaban, but in contrast, rivaroxaban falsely elevated functional protein S activity, regardless of the presence or absence of FVL. A total of 4/32 patients (12.5%) had low free protein S antigen (range, 58%–67%), whereas their functional protein S activity appeared normal (range 75%–130%).

The authors concluded that despite rivaroxaban treatment, APCR testing can distinguish FVL-HET from normal patients, rendering indiscriminate FVL DNA testing of all patients on rivaroxaban unnecessary. Free protein S should be tested in patients taking rivaroxaban to exclude hereditary protein S deficiency. The study was published in January 2018 in the journal Archives of Pathology & Laboratory Medicine.

Related Links:
Massachusetts General Hospital

Gold Member
Flocked Fiber Swabs
Puritan® Patented HydraFlock®
Verification Panels for Assay Development & QC
Seroconversion Panels
New
Typhoid Rapid Test
OnSite Typhoid IgG/IgM Combo Rapid Test
New
Hemoglobin/Haptoglobin Assay
IDK Hemoglobin/Haptoglobin Complex ELISA

Print article

Channels

Clinical Chemistry

view channel
Image: QIP-MS could predict and detect myeloma relapse earlier compared to currently used techniques (Photo courtesy of Adobe Stock)

Mass Spectrometry-Based Monitoring Technique to Predict and Identify Early Myeloma Relapse

Myeloma, a type of cancer that affects the bone marrow, is currently incurable, though many patients can live for over 10 years after diagnosis. However, around 1 in 5 individuals with myeloma have a high-risk... Read more

Immunology

view channel
Image: The cancer stem cell test can accurately choose more effective treatments (Photo courtesy of University of Cincinnati)

Stem Cell Test Predicts Treatment Outcome for Patients with Platinum-Resistant Ovarian Cancer

Epithelial ovarian cancer frequently responds to chemotherapy initially, but eventually, the tumor develops resistance to the therapy, leading to regrowth. This resistance is partially due to the activation... Read more

Technology

view channel
Image: Ziyang Wang and Shengxi Huang have developed a tool that enables precise insights into viral proteins and brain disease markers (Photo courtesy of Jeff Fitlow/Rice University)

Light Signature Algorithm to Enable Faster and More Precise Medical Diagnoses

Every material or molecule interacts with light in a unique way, creating a distinct pattern, much like a fingerprint. Optical spectroscopy, which involves shining a laser on a material and observing how... Read more

Industry

view channel
Image: The collaboration aims to leverage Oxford Nanopore\'s sequencing platform and Cepheid\'s GeneXpert system to advance the field of sequencing for infectious diseases (Photo courtesy of Cepheid)

Cepheid and Oxford Nanopore Technologies Partner on Advancing Automated Sequencing-Based Solutions

Cepheid (Sunnyvale, CA, USA), a leading molecular diagnostics company, and Oxford Nanopore Technologies (Oxford, UK), the company behind a new generation of sequencing-based molecular analysis technologies,... Read more
Copyright © 2000-2025 Globetech Media. All rights reserved.