Abstract
Background: Thrombotic thrombocytopenic purpura (TTP) is a life-threatening microangiopathic condition caused by an autoimmune or a genetic deficiency of ADAMTS13. Many ADAMTS13 activity assays are available that aid TTP diagnosis but their sensitivity and applicability are limited. Cattle-FRETS71 (C-71) is a bovine von Willebrand factor (VWF) domain A2-derived fluorogenic substrate that is equally cleaved by plasma ADAMTS13 of different species of research interest (e.g., mouse, rat, sheep, cattle). Therefore, the C-71 substrate would be ideal for both clinical and research applications within the same settings.
Aims: The objective of the current work was to validate the performance of C-71 substrate compared to FRETS-rVWF71 (H-71), an optimized ADAMTS13 substrate derived from the human VWF A2 domain but lacking additional C-71 advantages. Comparison with FRETS-VWF73 (H-73), the common commercial substrate also was sought.
Methods: Internal validation was performed using heparinized plasma samples previously analyzed by H-71 (n=89). External validation was a blinded study using serum samples (n=118) from the Oklahoma TTP-HUS registry that had been assayed by H-73 within 1 year of collection, in 2004-2014.
Results: In the 89 plasma samples (Fig 1A), the correlation between C-71 and H-71 was excellent (r = 0.95). There was 100% agreement (Kappa=1.0) between C-71 and H-71 when classifying patients into low ( < 10%) and normal (≥10) groups. In the 118 serum samples from the Registry (Fig 1B), the correlation between C-71 and H-73 was good (r = 0.81).There was 86% agreement (kappa=0.60) between C-71 and H-73 classifying patients as < 10% and ≥10%. Of the 17 misclassified patients, 15 were only < 10% on the C-71 assay and 2 were only < 10% on the H-73 assay.
Conclusion(s): Results were similar among C-71 and H-71 and classification into low/normal groups was the same. Less agreement between C-71 and H-73 may be caused by decreased ADAMTS13 activity during frozen storage.
Aims: The objective of the current work was to validate the performance of C-71 substrate compared to FRETS-rVWF71 (H-71), an optimized ADAMTS13 substrate derived from the human VWF A2 domain but lacking additional C-71 advantages. Comparison with FRETS-VWF73 (H-73), the common commercial substrate also was sought.
Methods: Internal validation was performed using heparinized plasma samples previously analyzed by H-71 (n=89). External validation was a blinded study using serum samples (n=118) from the Oklahoma TTP-HUS registry that had been assayed by H-73 within 1 year of collection, in 2004-2014.
Results: In the 89 plasma samples (Fig 1A), the correlation between C-71 and H-71 was excellent (r = 0.95). There was 100% agreement (Kappa=1.0) between C-71 and H-71 when classifying patients into low ( < 10%) and normal (≥10) groups. In the 118 serum samples from the Registry (Fig 1B), the correlation between C-71 and H-73 was good (r = 0.81).There was 86% agreement (kappa=0.60) between C-71 and H-73 classifying patients as < 10% and ≥10%. Of the 17 misclassified patients, 15 were only < 10% on the C-71 assay and 2 were only < 10% on the H-73 assay.
Conclusion(s): Results were similar among C-71 and H-71 and classification into low/normal groups was the same. Less agreement between C-71 and H-73 may be caused by decreased ADAMTS13 activity during frozen storage.
| Original language | American English |
|---|---|
| State | Published - 10 Jul 2022 |
| Event | The International Society on Thrombosis and Haemostasis 2022 Congress - England, London, United Kingdom Duration: 9 Jul 2022 → 13 Jul 2022 https://www.isth2022.org/ |
Conference
| Conference | The International Society on Thrombosis and Haemostasis 2022 Congress |
|---|---|
| Abbreviated title | ISTH 2022 Congress |
| Country/Territory | United Kingdom |
| City | London |
| Period | 9/07/22 → 13/07/22 |
| Internet address |