BLOOD COAGULATION TIMER

• US 3,821,643 A
• Filed: 05/29/1973
• Issued: 06/28/1974
• Est. Priority Date: 05/29/1973
• Status: Expired due to Term

• Current Assignee: Bostick W, Carr P
• Original Assignee: Bostick W, Carr P
• Inventors: BOSTICK W, CARR P
• Application Number:
  US05/364,278
• Time in Patent Office: 395 Days
• US Class Current: 324/722
• CPC Class Codes: G01N 33/4905 Determining clotting time of blood by chemical methods G01N33/86, C12Q1/54
• CPC Class Codes: G01R 17/105 for measuring impedance or resistance

Abstract

The clotting time of blood is determined at the instant of the initiation of clotting by detecting the sharp change in electrical resistance of a resistive circuit component having a large negative or positive temperature coefficient of resistance, immersed in the blood. The clotting time may be indicated visually, or audibly, or a time-temperature reading may be continuously recorded on a strip chart or the like or a combination of such indicators may be used.

Claims

1. A blood clotting indicating device comprising a blood sample holder, means for maintaining the holder and a blood sample containable therein at a constant temperature, a resistive circuit component having a large temperature coefficient of resistance, means mounting said resistive circuit component for movement in said sample holder, and circuit means for determining an abrupt change in the resistance of said resistive circuit component.

2. The invention defined in claim 1 wherein the resistive circuit component comprises a thermistor.

3. The invention defined in claim 1 wherein said resistive circuit component has a large negative temperature coefficient of resistance.

4. The invention defined in claim 1 wherein said resistive circuit component has a large positive temperature coefficient of resistance.