Heparin Monitoring Using Finger or Heel Stick Blood Samples in Pediatric Patients on a Near-patient Platform

Background: aPTT and anti-FXa are the most common tests to adjust dosage of heparin in pediatric patients requiring anticoagulation. However, the current anti-coagulation practice requires frequent blood draws (at least 1 mL) that can lead to iatrogenic anemia and potentially further blood transfusions. Here, we test the feasibility of utilizing ~60 µl finger/heel stick sample (FS) to perform aPTT, functional FXa and Antithrombin-III (ATIII) tests on a digital microfluidic (DMF) system that can be used for near-patient monitoring of heparin in children.

Methods: In a prospective research study, whole blood samples (33 for FXa and ATIII, 6 for aPTT) were collected by both venipuncture and FS from consented pediatric patients who were on heparin therapy post-cardiac surgery. Functional assays for FXa and ATIII, and an aPTT assay were performed on the DMF cartridge by loading one droplet of whole blood (venipuncture or FS) which was mixed with a droplet of specific activator, incubated for approximately 2 min at 37°C, followed by addition of specific substrate and measurement of fluorescence or absorbance. Results were compared between the two collection methods and to clinical laboratory reference method (obtained from hospital records).

Results: There was a strong correlation between venipuncture and FS samples tested on DMF platform for all the three assay. Bland-Altman plots show a good limits of agreement for both tests. A slight bias was observed between capillary and venous samples for aPTT. There was also a good correlation between DMF method vs. the clinical laboratory reference method for these assays.

Conclusion: Automated and rapid testing for heparin monitoring using low FS volumes on a DMF platform is feasible and will enable frequent monitoring in neonates and pediatric patients. The use of this near-patient technology in a clinical setting needs further investigation.

Presenting Author(s)

Ramakrishna S. Sista, PhD
Vice President Pediatric Diagnostics
Baebies, Inc.
Cary, North Carolina
Disclosure: Baebies (Employee)

Co-Author(s)

JC
Jacob Coyne, n/a
Scientist
Baebies, Inc.
Durham, North Carolina
Disclosure: Baebies Inc (Products/Services: R&D Research Scientist: development of a diagnostic heparin monitoring platform) (Employee)
MB
Michael Basmajian, n/a
Engineer
Baebies, Inc.
Durham, North Carolina
Disclosure: Baebies, Inc. (Products/Services: I'm an engineer at Baebies and have stock options.) (Employee, Stockholder/Ownership Interest (excluding diversified mutual funds))
JE
Jennifer Elderbroom, n/a
Scientist
Baebies, Inc.
Morrisville, North Carolina
Disclosure: Baebies (Products/Services: I am a scientist at Baebies and have stock ownership in the company.) (Employee, Ownership or partnership)
MB
Mike Boso, n/a
Engineer
Baebies, Inc.
Durham, North Carolina
Disclosure: Baebies (Products/Services: I am the Senior Staff Systems Engineer at Baebies. I have stock ownership in the company.) (Employee)
SE
Sirisha Emani, Ph.D.
Research Scientist
Boston Children's Hospital
Boston, Massachusetts
Disclosure: No Financial Relationships Disclosed
MD
Mamadou Diallo, n/a
Lab Technician
Boston Children's Hospital
Quincy, Massachusetts
Disclosure: No Financial Relationships Disclosed
ML
Melissa Langer, n/a
Scientist
Baebies, Inc.
615 Davis Dr, Suite 800, North Carolina
Disclosure: No Financial Relationships Disclosed
RN
Rainer Ng, n/a
Director, Technical Development
Baebies, Inc.
Durham, North Carolina
Disclosure: Baebies, Inc (Employee)
Sitaram E. Emani, MD
Associate Professor
Boston Children's Hospital
Boston, Massachusetts
Disclosure: No Financial Relationships Disclosed
Vamsee Pamula, PhD
Founder and President
Baebies, Inc.
Durham, North Carolina
Disclosure: Baebies, Inc. (Products/Services: I am the Founder and President of Baebies. I have stock ownership in the company.) (Employee, Stockholder/Ownership Interest (excluding diversified mutual funds))