A Novel Point-of-Care Whole Blood Coagulation Assay to Screen for Hemostatic Defects

S. Pourang¹, M. Suster¹, D. Maji¹, S. Butala², J. Nutt¹, L. Nayak^1,3, P. Mohseni¹, S. Ahuja^1,2

¹Case Western Reserve University, Cleveland, United States, ²Rainbow Babies & Children's Hospital, Cleveland, United States, ³University Hospitals Cleveland Medical Center, Cleveland, United States

Abstract Number: PB0641

Meeting: ISTH 2020 Congress

Theme: Diagnostics and OMICs » Laboratory Diagnostics

Background: Screening coagulation assays (PT/PTT) have poor sensitivity and specificity for detection of hemostatic defects. We have developed a novel, point-of-care (POC), whole blood assay based on a dielectric microsensor (ClotChip) that provides global coagulation assessment in a miniaturized, portable measurement platform

Aims: To assess the ClotChip sensitivity to detect hemostatic defects

Methods: Patients (n=37) presenting with bleeding symptoms or with abnormal coagulation screening pre-operatively, and undergoing a bleeding disorder work-up, were enrolled. Blood samples were obtained by venipuncture in 3.2% sodium citrate. Coagulation was induced with CaCl₂. ClotChip was based on the electronic technique of dielectric spectroscopy (DS) integrated into a disposable microfluidic channel with < 10 µL sample volume. ClotChip curves were calculated as variation in blood permittivity at 1MHz, and time to reach a peak in permittivity (T_peak) was taken as coagulation time. Sensitivity and specificity of ClotChip were calculated for detection of a hemostatic defect

Results: ClotChip exhibited mean T_peak of 435 ± 22 sec (mean ± SEM) for patients with clinically normal hemostatic function. Mean T_peak for patients with a hemostatic dysfunction was 751 ± 159 sec and was significantly prolonged (P=0.002) compared to patients in the normal group. A receiver operator characteristic (ROC) curve (Fig. 1)

[ROC Curve]

was generated to determine the true-positive rate (sensitivity) and false-positive rate (100% – specificity) for ClotChip T_peak to detect hemostatic dysfunction, and the area under the curve (AUC) for ClotChip T_peak was 0.88. The sensitivity and specificity of ClotChip T_peak with a threshold of 540 sec were determined as 78% and 93%, respectively (Table 1)

	Hemostatic Defect Present	Hemostatic Defect Absent	Total
ClotChip Abnormal	7 (True Positive)	2 (False Positive)	9
ClotChip Normal	2 (False Negative)	26 (True Negative)	28
Total	9	28	37

[Sensitivity and Specificity Results]

Conclusions: Our studies demonstrate a novel, microfluidic, dielectric sensor (ClotChip) was sensitive for detection of hemostatic defects. ClotChip has potential to fulfill an unmet clinical need as a POC tool to triage extensive work-up for bleeding symptoms or abnormal coagulation screening tests

To cite this abstract in AMA style:

Pourang S, Suster M, Maji D, Butala S, Nutt J, Nayak L, Mohseni P, Ahuja S. A Novel Point-of-Care Whole Blood Coagulation Assay to Screen for Hemostatic Defects [abstract]. Res Pract Thromb Haemost. 2020; 4 (Suppl 1). https://abstracts.isth.org/abstract/a-novel-point-of-care-whole-blood-coagulation-assay-to-screen-for-hemostatic-defects/. Accessed November 26, 2020.

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