Device for determining the activated clotting time of a blood sample

• US 4,105,411 A
• Filed: 08/31/1977
• Issued: 08/08/1978
• Est. Priority Date: 08/31/1977
• Status: Expired due to Term

• Current Assignee: Manufacturers Hanover Trust Co. (JP Morgan Chase & Co)
• Original Assignee: Sybron Corporation (Envista Holdings Corporation)
• Inventors: Biver, William R.
• Primary Examiner(s): Reese, Robert M.
• Application Number:
  US05/829,297
• Time in Patent Office: 342 Days
• Field of Search: 23/253 R, 23/230 B, 73/64.1
• US Class Current: 422/73
• CPC Class Codes: G01N 33/4905 Determining clotting time of blood by chemical methods G01N33/86, C12Q1/54

Abstract

Disclosed is a device for determining the activated clotting time of a blood sample, the device being a hand held unit for holding a glass tube containing the blood sample to be tested. The unit includes an electric heater for maintaining the blood sampe at 37° C and an electronic timer. A digital display on the unit can be selectively programmed to display either a temperature or a time function. Upon obtaining the desired temperature, the electronic timer is started and the blood sample is virtually observed in order to determine the elapsed time before the blood sample begins to clot.

Claims

1. A device for determining the activated coagulation time of whole blood comprising:

(a) a hand held housing;

(b) an upstanding portion on said housing defining a chamber for receiving a rubber capped glass tube containing a sample of blood to be tested;

(c) said upstanding portion having a window to observe the tube in said chamber;

(d) an electric heater in said housing for maintaining the glass tube and blood sample at substantially 37°

C;

(e) a timer in said housing; and

(f) means on said housing to manually start said timer when a blood sample enters the tube and to stop said timer when a clot is observed to form in the blood sample.

2. A device as in claim 1 wherein said housing has a groove adjacent said upstanding portion adapted to receive the rubber cap of the glass tube for clamping the tube in said chamber.

3. A device as in claim 1 including:

(a) an oscillator in said housing;

(b) a first frequency divider which together with said oscillator defines said timer;

(c) a control circuit to maintain said heater at about 37°

C, said control circuit producing an analog output signal representing the temperature of said heater;

(d) an analog-to-digital converter for transforming said analog output signal to a digital signal; and

(e) a second frequency divider which together with said oscillator drives said analog-to-digital converter.

4. A device as in claim 3 including a digital display on said housing and means to selectively display either the temperature of said heater or the contents of said timer on said digital display.

5. A device for determining the activated coagulation time of whole blood comprising:

(a) a hand held housing provided with a chamber for receiving a glass tube containing a sample of the blood to be tested;

(b) electric heater means in said chamber for maintaining the temperature of the tube and blood sample therein at substantially 37°

C;

(c) an electronic clock in said housing;

(d) digital display means on said housing for reading out the contents of said clock;

(e) a start/stop circuit in said housing operatively connected to said display means for selectively starting and stopping said display means while said electronic clock continues to operate, said circuit when restarting said display means producing a read out on said display means which represents the sum of the previous read-out plus the elapsed time since the last stop condition; and

(f) means for resetting said electronic clock to zero.

6. A device as set forth in claim 5 wherein said housing has a window to facilitate observation of a tube and blood sample in said chamber.

7. A device as set forth in claim 5 including clamp means on said housing for holding a glass tube in said chamber.

8. A device as set forth in claim 7 wherein said clamp means is a groove on said housing adjacent said chamber, said groove being adapted to receive therein a rubber cap used to seal the tube containing the blood sample.

9. A device as in claim 5 wherein said heater means comprises:

(a) a heating block in said chamber;

(b) control means maintaining said heating block at 37°

C and issuing a signal representing the temperature of said block; and

(c) an analog/digital converter to digitize said signal and calibrated to display on said digital display means the temperature of the blood sample being tested.

10. A device as in claim 9 including a time/temperature key on said housing operatively connected to said electronic clock, said analog/digital converter and said display, said key being operable to selectively connect either said clock or said converter to said display.

11. A device as in claim 9 wherein said electronic clock includes an oscillator and a first frequency divider, said oscillator and a second frequency divider driving said analog/digital converter.