Systems and methods for collecting fluid from a subject
Systems and methods for delivering to and/or receiving fluids or other materials, such as blood or interstitial fluid, from subjects, e.g., from the skin. Beading disruptors and/or capillaries may be used for facilitating the transport of fluids from a subject into a device. Beading disruptors may disrupt the “pooling” of bodily fluids such as blood on the surface of the skin and help influence flow in a desired way. A capillary may conduct flow of fluid in the device, e.g., to an inlet of a channel or other flow path that leads to a storage chamber. A vacuum (reduced pressure relative to ambient) may be used to receive fluid into the device, e.g., by using relatively low pressure to draw fluid into the inlet of a channel leading to a storage chamber. The vacuum source may be part of the device and have a volume that is larger than a recess of the fluid transporter that receives fluid from a surface.
1. A method of receiving bodily fluid from a subject, the method comprising:
applying, to the skin of a subject, a device comprising a fluid transporter having a recess and a flow activator, a channel having an inlet in fluid communication with the recess, and a vacuum source having a pressure less than ambient pressure, the recess positioned to collect bodily fluid on the skin of the subject that is released by the flow activator;
receiving a bodily fluid from the skin into the recess and into a groove positioned in the recess, the groove extending from the inlet and being in fluid communication with the inlet; and
moving the bodily fluid from the groove into the channel and toward the vacuum source due to a difference in pressure between the recess and the vacuum source.
2. The method of claim 1 , wherein the flow activator comprises one or more needles.
3. The method of claim 1 , wherein the fluid transporter has an opening, and wherein the inlet is positioned such that at least a portion of the inlet is positioned within about 0.7 millimeters of the opening of the fluid transporter.
4. The method of claim 1 , wherein the flow activator comprises one or more needles or microneedles.
5. The method of claim 1 , wherein the fluid transporter has a volume of no more than about 2 ml when the device is positioned against the skin of the subject.
6. The method of claim 1 , further comprising a seal arranged to control a fluid communication pathway between the vacuum source and the fluid transporter.
7. The method of claim 1 , wherein the vacuum source comprises a vacuum chamber having a pressure less than ambient pressure prior to introduction of a bodily fluid from the subject into the device.
8. The method of claim 7 , wherein the vacuum chamber has a pressure, prior to introduction of a bodily fluid from the subject into the device, that is less than about 100 mmHg below ambient pressure.
9. The method of claim 1 , wherein the groove comprises a capillary.
10. The method of claim 9 , wherein the capillary comprises a curved flow path.
11. A method of receiving bodily fluid from a subject, the method comprising:
applying, to the skin of a subject, a device comprising a fluid transporter having an opening, a recess and a flow activator, a channel having an inlet in fluid communication with the recess, and a vacuum source having a reduced pressure less than ambient pressure, the fluid transporter positioned to collect bodily fluid on the skin of the subject that is released by the flow activator;
opening fluid communication between the recess and the vacuum source;
receiving a bodily fluid into the recess and into a groove positioned in the recess, the groove forming a flow path along a surface that defines the recess, and the groove being in fluid communication with the inlet;
blocking the inlet with at least a portion of the bodily fluid;
increasing a pressure within the recess relative to a pressure in the vacuum source; and
moving the bodily fluid from the groove into the channel towards the vacuum source due to a difference in pressure between the recess and the vacuum source.
12. The method of claim 11 , wherein the inlet is positioned such that at least a portion of the inlet is positioned within about 0.7 millimeters of the opening of the fluid transporter.
13. The method of claim 11 , wherein the flow activator comprises one or more needles or microneedles.
14. The method of claim 11 , wherein the fluid transporter has a volume of no more than about 2 ml when the device is positioned against the skin of the subject.
15. The method of claim 11 , further comprising a seal arranged to control a fluid communication pathway between the recess and the vacuum source.
16. The method of claim 11 , wherein the vacuum source comprises a vacuum chamber having a pressure less than ambient pressure prior to introduction of a bodily fluid from the subject into the device.
17. The method of claim 16 , wherein the vacuum chamber has a pressure, prior to introduction of a bodily fluid from the subject into the device, that is less than about 100 mmHg below ambient pressure.
18. The method of claim 11 , wherein the inlet is positioned such that at least a portion of the inlet is positioned within a distance to the opening of about 10% of a distance between the opening and a point within the fluid transporter perpendicularly furthest away from the opening.
19. The method of claim 11 , wherein the fluid transporter and the opening together define a first volume, the vacuum source has a second volume, and a volumetric ratio of the first volume to the second volume is at least about 1:6.
20. The method of claim 11 , wherein the fluid transporter and the opening together define a first volume that is less than about 10 ml.
21. The method of claim 11 , wherein the vacuum source has a second volume that is less than about 10 ml.