Low-volume coagulation assay

Abstract

Compositions and methods for measuring coagulation parameters using very small volumes of blood are provided. Advantageously, the methods described herein can be performed from a single drop of blood (about 20 μL) while generally leaving enough sample to perform other measurements, optionally in a multiplexed format. The methods and devices do not require a skilled operator and can be performed at the point of service, which can be an important feature for managing blood coagulation disorders and treatments thereof.

1 - 49 . (canceled) 
     
     
         50 . A method for measuring coagulation time of a blood sample of a subject, comprising:
 (a) initiating a coagulation reaction of the blood sample of the subject;   (b) obtaining an optical signal from or a video of said coagulation reaction; and   (c) analyzing said optical signal or video to measure the coagulation time of said blood sample.   
     
     
         51 . The method of  claim 50 , wherein the method is performed at a point of service location. 
     
     
         52 . The method of  claim 50 , wherein at least a portion of a device is located at a point of service location for performing said initiating, obtaining, and analyzing. 
     
     
         53 . The method of  claim 52 , wherein the device is dynamically controlled through a cloud computing infrastructure. 
     
     
         54 . The method of  claim 50 , wherein:
 A) said initiating a coagulation reaction comprises initiating a coagulation reaction in a mixture comprising a quantity of an original biological sample, wherein the mixture: i) has a total volume of no greater than 200 microliters, ii) contains no greater than 20 microliters of the original biological sample, and iii) contains no greater than 80% by volume original biological sample;   B) said obtaining an optical signal from or obtaining a video of said coagulation reaction comprises illuminating the mixture and detecting an optical signal from the mixture; and   C) said analyzing said optical signal or video to measure coagulation time of said blood sample comprises analyzing the mixture for coagulation based on an analysis of the optical signal from the mixture.   
     
     
         55 . The method of  claim 54 , wherein the step of detecting the optical signal from the mixture comprises obtaining an image of the mixture and analyzing the image to identify a region of interest (ROI) of the image, wherein the region of interest of the image contains imaged information of the mixture. 
     
     
         56 - 61 . (canceled) 
     
     
         62 . The method of  claim 54 , wherein the optical signal is transmitted through the mixture and is detected over a period of time. 
     
     
         63 . The method of  claim 62 , wherein identifying a coagulation time of the mixture comprises an analysis comprising determining a time when the intensity of the optical signal transmitted through the mixture is reduced by a selected amount as compared to a baseline intensity of the optical signal transmitted through the mixture. 
     
     
         64 - 65 . (canceled) 
     
     
         66 . The method of  claim 54 , wherein the optical signal is scattered by the mixture and is detected over a period of time. 
     
     
         67 . The method of  claim 66 , further comprising identifying a coagulation time of the mixture based on an analysis comprising determining a time when the intensity of the optical signal scattered by the mixture is increased by a selected amount as compared to a baseline intensity of the optical signal scattered by the mixture. 
     
     
         68 . (canceled) 
     
     
         69 . The method of  claim 54 , wherein the optical signal is transmitted through or scattered by the mixture and is detected with a CCD sensor, CMOS sensor, photodiode, or photomultiplier tube (PMT). 
     
     
         70 . The method of  claim 54 , wherein the mixture comprises exogenous fibrinogen. 
     
     
         71 - 72 . (canceled) 
     
     
         73 . The method of  claim 54 , wherein the original biological sample is whole blood. 
     
     
         74 . The method of  claim 54 , wherein the original biological sample is plasma. 
     
     
         75 - 77 . (canceled) 
     
     
         78 . The method of  claim 54 , wherein the mixture is illuminated with a white light source 
     
     
         79 . The method of  claim 54 , wherein the mixture is illuminated with light of one or more selected wavelengths. 
     
     
         80 . The method of  claim 54 , wherein the mixture is illuminated with light from a light-emitting diode (LED).