A novel device for collecting and dispensing fingerstick blood for point of care testing

Abstract

The increased world-wide availability of point-of-care (POC) tests utilizing fingerstick blood has led to testing scenarios in which multiple separate fingersticks are performed during a single patient encounter, generating cumulative discomfort and reducing testing efficiency. We have developed a device capable of a) collection of up to 100 μL of fingerstick blood from a single fingerstick by capillary action, and b) dispensing this blood in variable increments set by the user. We tested the prototype device both in a controlled laboratory setting and in a fingerstick study involving naive device users, and found it to have accuracy and precision similar to a conventional pipettor. The users also found the device to be easy to use, and recommended minor ergonomic improvements. Our device would allow performance of multiple POC tests from a single fingerstick blood sample, thus providing a novel functionality that may be of use in many testing settings worldwide.

Dynamic and tunable metabolite control for robust minimal-equipment assessment of serum zinc

“…A simple 1:4 dilution can be easily performed with a fixed-volume pipette in the field and removes potential inaccuracies caused by minimally-trained personnel in precisely pipetting small sample volumes. A 200 μL test volume is sufficient for cell pellet visualization and requires only 50 μL of serum, a volume that can be reasonably be obtained from a finger-stick of blood 29 . Population data show that serum zinc concentrations fall between 2 and 20 μM 30 , so a test run in 25% serum must produce distinct colors across a range of 0.5–5 μM zinc.…”

SNAPflex: a paper-and-plastic device for instrument-free RNA and DNA extraction from whole blood

“…The SNAPflex device was designed with a final capacity of 1mL, including lysed sample and wash buffers. Keeping this constraint in mind, we have designed the SNAPflex lysis buffer to enable nucleic acid extraction from up to 200µL whole blood, as this volume can be obtained from pooled finger prick volumes (routine finger prick blood sampling yields 50-100µL 30,31 ).…”

From Point-of-Care Testing to eHealth Diagnostic Devices (eDiagnostics)

“…The delivery and availability of a biological fluid are parameters that would set specific constraints to an eDiagnostic device. For example, blood samples could be obtained using a finger-prick procedure or a dedicated blood collection device (e.g., TAP, Seventh Sense Biosystems Inc.) − and delivered to a device quantitatively using a capillary tube, but the device should be able to detect the target analyte in less than 100 μL of blood (volume that can be routinely collected from a finger prick or a blood collection device) and perform microscale blood plasma separation inside the device. Interstitial fluids could be obtained by using a fluid collection device that incorporates microneedles − or uses iontophoresis .…”