Capillary flow device

A method for performing a prothrombin time assay on a blood sample which comprises:

• a. adding said sample to an inlet port of an analytical device containing a capillary passageway used in a horizontal orientation for performing a prothrombin time assay on a blood sample, which comprises:
• i. a housing;
• ii. an inlet port in said housing;
• iii. a reaction chamber enclosed in said housing;
• iv. a capillary unit for transmitting, via capillary action, said sample from said inlet port to said reaction chamber, said inlet port, capillary unit, and reaction chamber together forming at least part of a horizontal capillary passageway when said housing is in its normal operating position;
• v. a measured amount of a dry reagent in said reaction chamber, wherein said reagent induces clotting of said sample;
• and
• vi. a vent for gases in said housing, said vent communicating with said reaction chamber to provide for exit of gases when sample enters said capillary passageway;
• b. permitting said sample to flow via capillary action from said inlet port through the capillary unit of said device into the reaction chamber;
• and
• c. detecting a change, if any, in viscosity of said sample by detecting interaction of light with particles in said capillary passageway as said sample reacts with the reagent in said capillary passageway, said change in viscosity occurring as a result of clotting of said sample.

An analytical system for performing a prothrombin time assay on a blood sample, which comprises:

• a. an electronic monitor comprising:
• i. means for emitting light;
• ii. means for detecting interaction of said light with particles in a fluid;
• iii. means for holding a capillary device containing a sample to be analyzed in a horizontal position so that said light interacts with said sample;
• b. a capillary device adapted to fit into said monitor and be retained by said means for holding, said capillary device comprising:
• i. a housing;
• ii. an inlet port in said housing;
• iii. a reaction chamber enclosed in said housing;
• iv. a capillary for transmitting, via capillary action, said sample from said inlet port to said reaction chamber, wherein said inlet port, capillary, and reaction chamber together form at least part of a horizontal capillary passageway when said housing is in its normal operating position;
• v. a dry reagent in said reaction chamber, wherein said reagent induces clotting of said sample;
• and
• vi. a vent for gases in said housing, said vent communicating with said reaction chamber to provide for exit of gases when sample enters said capillary passageway.