Protein S testing in patients with protein S deficiency, factor V Leiden, and rivaroxaban by North American Specialized Coagulation Laboratories

Smock, Kristi J.; Plumhoff, Elizabeth A.; Meijer, Piet; Hsu, Peihong; Zantek, Nicole D.; Heikal, Nahla; Cott, Elizabeth M. Van

doi:10.1160/th15-12-0918

Cited by 13 publications

(34 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Ultimately, the contributions of EQA data to the literature provide evidence that regulatory clearance for DOAC assays is needed to expand test availability and encourage standardization at the manufacturer level that could help minimize potentially clinically significant assay variability. 39 The all-method mean PS activity overestimated functional PS as compared with free PS antigen assays (mean PS activity 112%, mean free PS antigen 80%). In addition, PT-and Russell Viper Venom Time (RVVT)-based PS activity assays showed higher mean PS activity results than the aPTT-based PS activity assays, suggesting that PT-and RVVT-based PS activity assays are affected by rivaroxaban interference to a greater degree.…”

Section: Irec Tor Alanti Coag Ul Antsmentioning

confidence: 88%

“…A review of protein S (PS) testing performance in North American clinical laboratories from 2010 to 2012 through the NASCOLA program included evaluation of one normal pooled plasma sample spiked with 200 ng/mL rivaroxaban . The all‐method mean PS activity overestimated functional PS as compared with free PS antigen assays (mean PS activity 112%, mean free PS antigen 80%).…”

Section: Direct Oral Anticoagulantsmentioning

confidence: 99%

“…The all‐method mean PS activity overestimated functional PS as compared with free PS antigen assays (mean PS activity 112%, mean free PS antigen 80%). In addition, PT‐ and Russell Viper Venom Time (RVVT)‐based PS activity assays showed higher mean PS activity results than the aPTT‐based PS activity assays, suggesting that PT‐ and RVVT‐based PS activity assays are affected by rivaroxaban interference to a greater degree …”

Section: Direct Oral Anticoagulantsmentioning

confidence: 99%

“…In addition, PT-and Russell Viper Venom Time (RVVT)-based PS activity assays showed higher mean PS activity results than the aPTT-based PS activity assays, suggesting that PT-and RVVT-based PS activity assays are affected by rivaroxaban interference to a greater degree. 39 The Belgian national External Quality Assessment Scheme (EQAS) has published results of two studies in which it sent normal pooled plasma samples spiked with differing concentrations of dabigatran, rivaroxaban, and apixaban to approximately 190 participating laboratories for measurement of routine coagulation assays as well as antithrombin (AT) activity. 40,41 Laboratories that used AT activity assays based on inhibition of thrombin tended to overestimate antithrombin activity in the presence of 250 μg/L dabigatran.…”

Section: Irec Tor Alanti Coag Ul Antsmentioning

confidence: 99%

See 3 more Smart Citations

What have we learned from coagulation laboratory participation in external quality programs?

Smock

Moser

2019

Int J Lab Hematology

View full text Add to dashboard Cite

Coagulation laboratory external quality assurance (EQA) programs provide information that satisfies regulatory requirements and improves laboratory quality, patient care, and safety. In addition to the value to individual laboratories, data from EQA programs benefits the laboratory community in multiple ways by providing a snapshot of laboratory practice and summarizing the performance of various methods in identifying normal and abnormal specimens and the effects of therapies or interfering substances. This review article aims to summarize and provide examples of some of the important lessons learned from coagulation EQA data, including issues related to non‐standardization, imprecision, and the effects of interfering substances.

show abstract

Section: Irec Tor Alanti Coag Ul Antsmentioning

confidence: 88%

Section: Direct Oral Anticoagulantsmentioning

confidence: 99%

Section: Direct Oral Anticoagulantsmentioning

confidence: 99%

Section: Irec Tor Alanti Coag Ul Antsmentioning

confidence: 99%

See 2 more Smart Citations

What have we learned from coagulation laboratory participation in external quality programs?

Smock

Moser

2019

Int J Lab Hematology

View full text Add to dashboard Cite

show abstract

“…Protein S is a Vitamin K‐dependent anticoagulant protein encoded by the PROS‐1 gene that is mainly synthesized in the liver and endothelial cells. It works as a cofactor of activated protein C (APC) in the inactivation of coagulation factors Va and VIIIa . In addition, it has APC‐independent anticoagulant activity through its direct inhibition of prothrombinase and tenase activity .…”

Section: Introductionmentioning

confidence: 99%

Evaluation of the plasma protein S dynamics during pregnancy using a total protein S assay: Protein S‐specific activity decreased from the second trimester

Takeuchi¹,

Adachi²,

Tsuda³

et al. 2020

J of Obstet and Gynaecol

View full text Add to dashboard Cite

Aim The relationship between congenital protein S (PS) deficiency and complications during pregnancy remains unclear, partly due to the difficulty of precisely evaluating the PS level with conventional assays and the physiological decrease of PS during pregnancy. A new PS assay was developed to measure the total PS antigen and activity quantitatively and calculate PS‐specific activity. This study aimed to evaluate the plasma PS dynamics during pregnancy using the new PS assay and establish the reference interval for pregnant women. Methods A total of 253 pregnant women without a personal or family history of thromboembolism were recruited. Blood samples were obtained in the first, second and third trimesters and at one month post‐partum. The total PS antigen, activity, and PS‐specific activity were studied. Results were analyzed by the repeated measures single‐factor anovas followed by a post‐hoc test using Excel Statistics. Results The mean ± standard deviation (IU/mL) of the total PS antigen levels in the first, second and third trimesters and 1 month post‐partum were 0.67 ± 0.12, 0.67 ± 0.09, 0.68 ± 0.11 and 0.92 ± 0.13, respectively. The total PS activity (IU/mL) in the first, second and third trimesters and 1 month post‐partum were 0.69 ± 0.14, 0.59 ± 0.10, 0.58 ± 0.12 and 0.87 ± 0.15, respectively. The PS‐specific activity was within the normal range of nonpregnant women in the first trimester (1.02 ± 0.10) but decreased in the second and third trimesters (0.88 ± 0.09 and 0.85 ± 0.09, respectively) before increasing in the post‐partum period (0.94 ± 0.08). Conclusion The total PS antigen and activity decrease throughout pregnancy, while the PS‐specific activity decreases in the second and third trimesters.

show abstract

Testing for dabigatran and rivaroxaban by clinical laboratories

et al. 2016

Self Cite

View full text Add to dashboard Cite

Rivaroxaban and dabigatran are among the newest anticoagulants, and measuring their concentration in patients is a new challenge for clinical laboratories. We analyzed data from the ECAT proficiency program to determine how well the assays are performing in clinical laboratories internationally. Most laboratories received a passing grade (Z score <3) for the results of their dabigatran and rivaroxaban testing. Failing Z scores were not associated with any particular method. With dabigatran, some homemade calibrators gave higher results than the commercially available calibrators. There were no significant differences among the instruments or the 5 reagents in use, but results showed inter-laboratory variability that could have clinical significance. The 3 reagents with the lowest number of users had poor inter-laboratory precision. Ten different anti-Xa reagents were in use for rivaroxaban testing. One reagent gave lower results than other reagents at 100 ng/mL but not at 300 ng/mL. There were no significant differences among the different rivaroxaban calibrators or instruments. In conclusion, inter-laboratory precision could be improved for both dabigatran and rivaroxaban assays. Homemade dabigatran calibrators differed from commercially available calibrators, and there was a statistically significant difference between some of the rivaroxaban reagents. About 10% of results received failing Z scores or passed but fell in a range that require the laboratory to investigate for bias or other inaccuracy in their method. Am. J. Hematol. 91:E464-E467, 2016. © 2016 Wiley Periodicals, Inc.

show abstract

Protein S testing in patients with protein S deficiency, factor V Leiden, and rivaroxaban by North American Specialized Coagulation Laboratories

Cited by 13 publications

References 22 publications

What have we learned from coagulation laboratory participation in external quality programs?

What have we learned from coagulation laboratory participation in external quality programs?

Evaluation of the plasma protein S dynamics during pregnancy using a total protein S assay: Protein S‐specific activity decreased from the second trimester

Testing for dabigatran and rivaroxaban by clinical laboratories

Contact Info

Product

Resources

About