Automated method and device for identifying and quantifying platelets and for determining platelet activation state using whole blood samples

An automated process for accurately determining the parameters of platelet count, platelet volume, platelet dry mass, and platelet component concentration on a cell-by-cell basis and for discriminating platelets from other cells in a normal or an abnormal whole blood sample, comprising the steps of:

• a) analyzing an aliquot of said sample essentially one cell at a time through a focused light source to produce a forward light scattering pattern representing scattered light intensity per unit scattering angle as a function of the scattering angle, said light scattering intensity measured over two angle intervals, the intervals being an approximately 5 to 20 degree high angle interval and an approximately 1 to 5 degree low angle interval, in two optical channels at increased first and second optical channel signal gains to produce two scattering intensity measurements sufficient to resolve platelets from non-platelets in said sample, wherein said first optical channel signal value derives from an increase in the gain of a high angle detector and said second optical channel signal value derives from an increase in the gain of a low angle detector;
• b) converting said first and second optical channel light scattering signal gain values to a platelet volume value and a refractive index value of said platelets;
• c) converting said platelet refractive index value to a platelet component concentration value;
• d) computing a platelet dry mass value as a product of said platelet component concentration value and said platelet volume value of steps b) and c);
• e) displaying histograms of said platelet volumes, platelet component concentrations, and platelet dry masses;
• and
• f) determining said platelet count based on particle volume and refractive index by placing said platelets within said volume versus refractive index map.

An automated apparatus for accurately determining the parameters of platelet count, platelet volume, platelet dry mass, and platelet component concentration and for discriminating platelets from other cells in a normal or an abnormal whole blood sample, comprising:

• a) means for analyzing an aliquot of said sample essentially one cell at a time through a focused light source to produce a forward light scattering pattern representing scattered light intensity per unit scattering angle as a function of the scattering angle, said light scattering intensity measured over two angle intervals, the intervals being an approximately 5 to 20 degree high angle interval and an approximately 1 to 5 degree low angle interval, in two optical channels at expanded first and second optical channel signal gains to produce two scattering intensity measurements sufficient to resolve platelets from non-platelets in said sample, wherein said first optical channel signal value derives from an increase in the gain of a high angle detector and said second optical channel signal value derives from an increase in the gain of a low angle detector;
• b) means for converting said first and second optical channel light scattering signal gain values to a platelet volume value and a refractive index value of said platelets;
• c) means for converting said platelet refractive index value to a platelet component concentration value;
• d) means for computing a platelet dry mass value as a function of the product of said platelet component concentration value and said platelet volume value of steps b) and c);
• e) means for displaying histograms of said platelet volumes, platelet component concentrations, and platelet dry masses;
• and
• f) means for determining said platelet count based on particle volume and refractive index by placing said platelets within said volume versus refractive index map.

An automated apparatus for accurately discriminating platelets from other cells on a cell-by-cell basis in a normal or an abnormal whole blood sample and for determining qualitative and quantitative blood platelet parameters, comprising:

• a) means for analyzing an aliquot of said sample essentially one cell at a time through a focused light source to produce a forward light scattering pattern representing scattered light intensity per unit scattering angle as a function of the scattering angle, said light scattering intensity measured over two angle intervals, the intervals being an approximately 5 to 20 degree high angle interval and an approximately 1 to 5 degree low angle interval, in two optical channels at increased first and second optical channel signal gains to produce two scattering intensity measurements sufficient to resolve platelets from non-platelets in said sample, wherein said first optical channel signal value derives from an increase in the gain of a high angle detector and said second optical channel signal value derives from an increase in the gain of a low angle detector;
• b) means for converting said first and second optical channel light scattering signal gain values to a platelet volume value and a refractive index value of said platelets;
• c) means for converting said platelet refractive index value to a platelet component concentration value;
• d) means for computing a platelet dry mass value as a function of the product of said platelet component concentration value and said platelet volume value of step b) and c);
• e) means for displaying histograms of said platelet volumes, platelet component concentrations, and platelet dry masses;
• and
• f) means for resolving said platelets from said non-platelets in said sample and determining said platelet parameters by placement within a volume versus refractive index map.