Methods of measuring hematocrit in fluidic channels including conductivity sensor
A device and a method of using the device for determining hematocrit in a whole blood sample. The device includes a first portion having an introducer, at least one fluid channel, a fluid actuator, and an analysis sensor and conductivity sensor disposed within the fluid channel. The second portion includes at least one well containing at least one material. The first portion and second portion are movable with respect to each other. The introducer is configured to transfer at least a portion of the material from the well in portion two into the fluid channel of portion one. The method includes measuring the resistance over substantially the entire portion of a whole blood sample and calculating an average hematocrit level of the whole blood sample based on the measured resistance.
1 . A system for determining hematocrit level in a blood sample, the system comprising:
a first portion, the first portion comprising:
at least one fluid channel, wherein the fluid channel is a microfluidic channel;
a fluid actuator;
an analyte sensor disposed within the fluid channel;
a conductivity sensor comprising at least two electrodes, the conductivity sensor disposed within the fluid channel upstream of the analyte sensor; and
an introducer; and
a second portion, the second portion comprising at least one well configured to hold at least one material;
wherein at least one of the first and second portions is moveable with respect to the other; and
wherein the introducer is configured to obtain at least a portion of the material from the at least one well and deliver it to the fluid channel, and wherein the fluid actuator is configured to move at least a portion of the material in the fluid channel to allow the hematocrit level of the blood sample to be determined.
2 . The system of claim 1 , wherein the conductivity sensor is configured to measure a resistance within the fluid channel.
3 . The system of claim 2 , wherein the system is configured to determine the hematocrit level of the blood sample using the measured resistance.
4 . The system of claim 1 , wherein the blood sample is a whole blood sample, and the determined hematocrit level is an average hematocrit level of substantially the entire portion of the whole blood sample.
5 . The system of claim 4 , wherein substantially the entire portion of the whole blood sample is at least 75% of the whole blood sample.
6 . The system of claim 4 , wherein substantially the entire portion of the whole blood sample is at least 85% of the whole blood sample.
7 . The system of claim 4 , wherein substantially the entire portion of the whole blood sample is at least 95% of the whole blood sample.
8 . The system of claim 1 , wherein the conductivity sensor is located adjacent to the introducer upstream of the analyte sensor.
9 . The system of claim 1 , wherein the at least two electrodes are located no more than 3 mm away from each other.
10 . The system of claim 1 , wherein the at least two electrodes are located no more than 1 mm away from each other.
11 . The system of claim 1 , wherein the analyte sensor is a resonator sensor.
12 . The system of claim 1 , wherein the at least two electrodes comprise a substantially chemically inert material.
13 . A method of determining hematocrit level in a whole blood sample utilizing a fluidic device, the method comprising:
moving the whole blood sample in a fluidic channel of the fluidic device, wherein the fluidic channel is a microfluidic channel;
detecting a resistance at a conductivity sensor in the fluidic channel, wherein the conductivity sensor comprises at least two electrodes, and wherein the conductivity sensor is located upstream of an analyte sensor in the fluidic channel;
measuring, at the conductivity sensor, the resistance over substantially the entire portion of the whole blood sample; and
calculating the hematocrit level of the whole blood sample based on the measured resistance at the conductivity sensor.
14 . The method according to claim 13 , wherein substantially the entire portion of the whole blood sample is at least 75% of the whole blood sample.
15 . The method according to claim 13 , wherein substantially the entire portion of the whole blood sample is at least 85% of the whole blood sample.
16 . The method according to claim 13 , wherein substantially the entire portion of the whole blood sample is at least 95% of the whole blood sample.
17 . The method according to claim 13 , wherein the hematocrit level of the whole blood sample is calculated by integrating the area under a curve of time versus the measured resistance.
18 . The method according to claim 13 , wherein the calculated hematocrit level is an average hematocrit level of substantially the entire portion of the whole blood sample.
19 . The method according to claim 13 , wherein the at least two electrodes are located no more than 10 mm away from each other.
20 . The method according to claim 13 , wherein the at least two electrodes are located no more than 3 mm away from each other.
21 . The method according to claim 13 , wherein the at least two electrodes are located no more than 1 mm away from each other.