US3812425A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method and apparatus for determination of hematocrit
Assignee: Becton Dickinson and Co
•
Filing: 1972-11-21
•
Granted: 1974-05-21
•
Expires: 1992-11-21
Abstract
Abstract A diluted blood sample is passed through a blood cell sensor of the type that provides an electric pulse having a peak amplitude corresponding to the volume of each sensed blood cell and a pulse width corresponding to the instantaneous flow rate of the blood sample through the sensor. The pulse amplitude is monitored and when the pulse peak is sensed, a signal corresponding to the pulse peak amplitude is stored and provided to a gate. A predetermined portion of the pulse width is detected and a signal having a width corresponding to the predetermined portion of the pulse width is provided to control the gate so that the gate passes the signal corresponding to the pulse peak amplitude only during the predetermined portion of the pulse width. The signal passed by the gate is integrated during a specified count period to develop an analog signal corresponding to hematocrit.
Inventors
- 👤 J Miller
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 23:53
CPC Classifications
G; G01; G01N; G01N15/00; G01N15/10; G01N15/1031; G01N15/12; G01N15/131; G01N15/132
Claims Analysis
Total Claims: 20
Claim 1
Independent Claim
116 words
A method for determining the hematocrit of a diluted blood sample, comprising the steps of: sensing the blood cells contained in the diluted blood sample by passing the sample through a sensing means; providing an electric pulse output for each sensed blood cell, each output pulse having a peak amplitude corresponding to the volume of the sensed blood cell and width corresponding to the instantaneous flow rate of the sample through the sensing means; sensing a predetermined portion of each output; modifying each output to have a duration corresponding to the sensed predetermined portion of the output; and integrating the modified output during a precisely repeatable period of time to provide an output corresponding to hematocrit.
Claim 2
Independent Claim
116 words
A method for determining the hematocrit of a diluted blood sample, comprising the steps of: sensing the blood cells contained in the diluted blood sample by passing the sample through a sensing means; providing an electric pulse output for each sensed blood cell, each output pulse having a peak amplitude corresponding to the volume of the sensed blood cell and width corresponding to the instantaneous flow rate of the sample through the sensing means; sensing a predetermined portion of each output; modifying each output to have a duration corresponding to the sensed predetermined portion of the output; and integrating the modified output during a precisely repeatable period of time to provide an output corresponding to hematocrit.
Claim 3
Dependent Claim
28 words
A method as described in claim 1, wherein the step of modifying each output includes the step of gating the output during the predetermined portion of the output.
Claim 4
Dependent Claim
31 words
A method as described in claim 2, additionally comprising the step of providing a signal during the sensed predetermined portion of each output, said gating being in response to the signal.
Claim 5
Dependent Claim
81 words
A method as described in claim 1, wherein the peak level of the output corresponds to blood cell volume, additionally including the steps of: providing an amplitude signal for each output, said amplitude signal having an amplitude corresponding to the output peak amplitude; modifying each amplitude signal to have a duration corresponding to the sensed predetermined portion of the associated output; and integrating the modified amplitude signals during a precisely repeatable period of time to provide an output corresponding to hematocrit.
Claim 6
Dependent Claim
54 words
A method as described in claim 1, wherein the step of sensing the predetermined portion of each output comprises the steps of: detecting the peak level of each output; and detecting when the trailing edge of the output decreases to a level equal to a predetermined fraction of the peak level of the output.
Claim 7
Dependent Claim
85 words
A method as described in claim 1, wherein the first mentioned step comprises the steps of: passIng the blood sample through an aperture; applying an electronic signal across the blood sample in the aperture; and detecting changes in signal level caused by the passage of blood cells through the aperture and forming pulses corresponding to the changes in signal level, said pulses having peak amplitudes corresponding to blood cell volumes and durations corresponding to the instantaneous flow rate of the blood sample through the aperture.
Claim 8
Dependent Claim
122 words
An instrument for determining the hematocrit of a diluted blood sample, comprising: sensing means for sensing blood cells in the diluted blood sample and for providing an output for each sensed blood cell, said output having an amplitude corresponding to blood cell volume and a duration corresponding to the instantaneous flow rate of the blood sample through the sensing means; means for passing the blood sample through the sensing means; means for detecting a predetermined portion of each output; means responsive to the detecting means for providing modified output signals having durations corresponding to the predetermined portion of the outputs; and means for integrating the modified output signals over a precisely repeatable period of time to provide an output corresponding to hematocrit.
Claim 9
Dependent Claim
122 words
An instrument for determining the hematocrit of a diluted blood sample, comprising: sensing means for sensing blood cells in the diluted blood sample and for providing an output for each sensed blood cell, said output having an amplitude corresponding to blood cell volume and a duration corresponding to the instantaneous flow rate of the blood sample through the sensing means; means for passing the blood sample through the sensing means; means for detecting a predetermined portion of each output; means responsive to the detecting means for providing modified output signals having durations corresponding to the predetermined portion of the outputs; and means for integrating the modified output signals over a precisely repeatable period of time to provide an output corresponding to hematocrit.
Claim 10
Dependent Claim
114 words
An instrument for determining the hematocrit of a diluted blood sample, as described in claim 7, wherein the sensing means comprises: an aperture; means for passing the blood sample through the aperture; means for applying an electronic signal across the blood sample in the aperture; and means for detecting modulation of the electronic signal and for forming pulses corresponding to the modulation which results from a change in resistance across the blood sample in the aperture as blood cells pass through the aperture, said pulses having a peak amplitude corresponding to the volume of the blood cells sensed and a duration corresponding to the instantaneous flow rate of the blood sample through the aperture.
Claim 11
Dependent Claim
45 words
An instrument for determining the hematocrit of a diluted blood sample as described in claim 7, wherein the means for providing modified output signals comprises a gate means for passing the output during a period of time corresponding to the predetermined portion of the output.
Claim 12
Dependent Claim
75 words
An instrument for determining the hematocrit of a diluted blood sample as described in claim 7, wherein the means for detecting the predetermined portion of each output includes, detector means for detecting the output peaks and levels of the trailing edges of the outputs equal to a specified fraction of the output peak levels and for providing a duration signal during the intervals between the output peaks and the specified fraction of the output peak.
Claim 13
Dependent Claim
43 words
An instrument for determining the hematocrit of a diluted blood sample as described in claim 10, wherein the means for providing modified output signals is a gate means responsive to the duration signals for passing the output when a duration signal is present.
Claim 14
Dependent Claim
69 words
An instrument for determining the hematocrit of a diluted blood sample as described in claim 7, additionally comprising: a peak detector means for providing a pulse when the output peak occurs; and output tracking means for tracking the output and for storing the output signal level in response to the pulse from the peak detector means so as to provide an amplitude signal corresponding to the output peak amplitude.
Claim 15
Dependent Claim
169 words
An instrument for determining the hematocrit of a diluted blood sample, comprising: sensing means for sensing blood cells contained in the diluted blood sample and for each sensed blood cell providing an output pulse having a peak amplitude corresponding to the cell volume and a duration corresponding to the instantaneous flow rate of the diluted blood sample through the sensing means; means for passing the blood sample through the sensing means; means responsive to the output pulses for detecting when the pulse peaks occur and for pRoviding signals in response thereto; means responsive to the signals from the pulse peak detecting means and the last mentioned means and for providing an output during the interval between said signals; gating means responsive to the output from the last mentioned means for passing the signals corresponding to the amplitudes of the pulse peaks; and integrating means for integrating the signals passed by the gating means over a precisely repeatable period of time so that a voltage corresponding to hematocrit is developed.
Claim 16
Dependent Claim
169 words
An instrument for determining the hematocrit of a diluted blood sample, comprising: sensing means for sensing blood cells contained in the diluted blood sample and for each sensed blood cell providing an output pulse having a peak amplitude corresponding to the cell volume and a duration corresponding to the instantaneous flow rate of the diluted blood sample through the sensing means; means for passing the blood sample through the sensing means; means responsive to the output pulses for detecting when the pulse peaks occur and for pRoviding signals in response thereto; means responsive to the signals from the pulse peak detecting means and the last mentioned means and for providing an output during the interval between said signals; gating means responsive to the output from the last mentioned means for passing the signals corresponding to the amplitudes of the pulse peaks; and integrating means for integrating the signals passed by the gating means over a precisely repeatable period of time so that a voltage corresponding to hematocrit is developed.
Claim 17
Independent Claim
111 words
A method for determining the hematocrit of a diluted blood sample, comprising the steps of: sensing the blood cells contained in the diluted blood sample by passing the sample through a sensing means; providing an output for each sensed blood cell, each output having a peak altitude corresponding to the cell volume and a width corresponding to the instantaneous flow rate of the sample through the sensing means; providing a signal for each output, said signal corresponding to the peak amplitude of the output and a portion of the width of the output; and integrating the signals during a precisely repeatable period of time to provide an output corresponding to hematocrit.
Claim 18
Independent Claim
111 words
A method for determining the hematocrit of a diluted blood sample, comprising the steps of: sensing the blood cells contained in the diluted blood sample by passing the sample through a sensing means; providing an output for each sensed blood cell, each output having a peak altitude corresponding to the cell volume and a width corresponding to the instantaneous flow rate of the sample through the sensing means; providing a signal for each output, said signal corresponding to the peak amplitude of the output and a portion of the width of the output; and integrating the signals during a precisely repeatable period of time to provide an output corresponding to hematocrit.
Claim 19
Dependent Claim
125 words
An instrument for determining the hematocrit of a dilute blood sample, comprising: sensing means for sensing blood cells in the diluted blood sample and for providing an output for each sensed cell, said output having a peak amplitude corresponding to blood cell volume and a width corresponding to the instantaneous flow rate of the blood sample through the sensing means; means for passing the blood sample through the sensing means; means responsive to the output of the sensing means for providing a signal for each output, said signal corresponding to the peak amplitude of the output and a portion of the width of the output; and means for integrating the signals over a precisely repeatable period of time to provide an output corresponding to hematocrit.
Claim 20
Dependent Claim
125 words
An instrument for determining the hematocrit of a dilute blood sample, comprising: sensing means for sensing blood cells in the diluted blood sample and for providing an output for each sensed cell, said output having a peak amplitude corresponding to blood cell volume and a width corresponding to the instantaneous flow rate of the blood sample through the sensing means; means for passing the blood sample through the sensing means; means responsive to the output of the sensing means for providing a signal for each output, said signal corresponding to the peak amplitude of the output and a portion of the width of the output; and means for integrating the signals over a precisely repeatable period of time to provide an output corresponding to hematocrit.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-05-20 | 1977-11-19 | 1978-05-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-05-20 | 1981-11-19 | 1982-05-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-05-20 | 1985-11-19 | 1986-05-21 | $7700.00 | Window Closed / Lapsed |