A method for determining the volume of a blood sample, the fraction of the blood sample volume composed of plasma, and the fraction of the blood sample volume composed of red blood cells, the method comprising: a) collecting the blood sample on a collection device, the collection device comprising an absorbent material capable of collecting the blood sample by capillary action and producing an observable colorimetric pattern from the blood sample; b) drying the blood sample on the collection device; c) recording the colorimetric pattern on the collection device as a first set of data points comprising grayscale values and pixel counts with an imaging device; and d) receiving and analyzing the first set of data points from the imaging device with a computing device operatively connected to the imaging device comprising an executable software program and a database comprising grayscale values from images of dried blood samples with known hematocrit levels, pixel counts from images of dried blood samples with known volume levels, and data from dried blood samples where the volume, area and hematocrit are known for each sample, wherein the executable software program performs the steps of: analyzing the grayscale value of the blood sample with grayscale values from images of dried blood samples with known hematocrit levels in the database to derive a hematocrit value of the liquid blood sample that was dried onto the collection device; analyzing the pixel count of the blood sample with pixel counts from images of dried blood samples with known volume levels in the database to derive an area value; analyzing the hematocrit value and the area value in the database with data from dried blood samples where the volume, area and hematocrit are known for each sample to derive a volume result; deriving from the volume result i) the volume of the blood sample collected by the collection device, ii) the fraction of the blood sample volume composed of plasma, and iii) the fraction of the blood sample volume composed of red blood cells. a) collecting the blood sample on a collection device, the collection device comprising an absorbent material capable of collecting the blood sample by capillary action and producing an observable colorimetric pattern from the blood sample; b) drying the blood sample on the collection device; c) recording the colorimetric pattern on the collection device as a first set of data points comprising grayscale values and pixel counts with an imaging device; and d) receiving and analyzing the first set of data points from the imaging device with a computing device operatively connected to the imaging device comprising an executable software program and a database comprising grayscale values from images of dried blood samples with known hematocrit levels, pixel counts from images of dried blood samples with known volume levels, and data from dried blood samples where the volume, area and hematocrit are known for each sample, wherein the executable software program performs the steps of: analyzing the grayscale value of the blood sample with grayscale values from images of dried blood samples with known hematocrit levels in the database to derive a hematocrit value of the liquid blood sample that was dried onto the collection device; analyzing the pixel count of the blood sample with pixel counts from images of dried blood samples with known volume levels in the database to derive an area value; analyzing the hematocrit value and the area value in the database with data from dried blood samples where the volume, area and hematocrit are known for each sample to derive a volume result; deriving from the volume result i) the volume of the blood sample collected by the collection device, ii) the fraction of the blood sample volume composed of plasma, and iii) the fraction of the blood sample volume composed of red blood cells. analyzing the grayscale value of the blood sample with grayscale values from images of dried blood samples with known hematocrit levels in the database to derive a hematocrit value of the liquid blood sample that was dried onto the collection device; analyzing the pixel count of the blood sample with pixel counts from images of dried blood samples with known volume levels in the database to derive an area value; analyzing the hematocrit value and the area value in the database with data from dried blood samples where the volume, area and hematocrit are known for each sample to derive a volume result; deriving from the volume result i) the volume of the blood sample collected by the collection device, ii) the fraction of the blood sample volume composed of plasma, and iii) the fraction of the blood sample volume composed of red blood cells.