Hematology system

• US 3,973,189 A
• Filed: 01/27/1975
• Issued: 08/03/1976
• Est. Priority Date: 05/15/1972
• Status: Expired due to Term

• Current Assignee: Baker Instruments Corporation
• Original Assignee: General Science Corporation
• Inventors: Angel, Henry R., Hennessy, James W., Oefinger, Arthur R.
• Primary Examiner(s): Corbin, John K.
• Assistant Examiner(s): Hille, Rolf
• Application Number:
  US05/544,643
• Time in Patent Office: 554 Days
• Field of Search: 324/71 CP
• US Class Current: 377/50
• CPC Class Codes: G01N 15/12 by observing changes in resistance or impedance across apertures when traversed by individual particles, e.g. by using the Coulter principle

Abstract

A system for counting electrical pulses representing red and white blood cells and for determining hematocrit, mean corpuscular volume and hemoglobin in association with the blood cell counts. The system includes a blood cell transducer through which a blood sample is caused to flow and operative to produce electrical pulses in response to the passage of cells through a metering aperture. Red and white blood cell counts are electronically accumulated during respective analytical runs and logic circuitry is provided for determining, during a red blood cell counting run, mean corpuscular volume and hematocrit. The system can also include correction circuitry to correct for the coincident passage of cells through the metering aperture.

Claims

1. A blood cell analysis system comprising:

means for providing electrical pulses in response to blood cells suspended in a liquid sample passing through an aperture through which said sample liquid is caused to flow;

means including a selected threshold level and operative in response to said electrical pulses having an amplitude above said threshold level to provide cell output pulses;

means for providing a start signal representative of the commencement of an analytical run;

a counter enabled by said start signal and operative in response to said cell output pulses to provide a predetermined fixed number of counter output pulses;

a first linear gate enabled by said start signal and operative to provide a predetermined number of gate output pulses each of a height proportional to the volume of a corresponding blood cell in response to said electrical pulses and said predetermined fixed number of received counter output pulses;

a peak detector operative in response to said gate output pulses to provide detector output pulses each having a uniform amplitude representative of the peak amplitude of corresponding ones of said gate output pulses and representative of the volume of a corresponding blood cell;

a first multivibrator receiving said cell output pulses and providing uniform width gating pulses;

a second linear gate receiving said detector output pulses and said uniform width gating pulses and providing a predetermined number of output pulses each of the same width and of a uniform amplitude representative of the amplitude of corresponding ones of said detector output pulses;

a first integrator operative in response to the output pulses from said second linear gate to provide a calibrated analog output signal representative of mean corpuscular volume;

divider means operative in response to said cell output pulses to provide a plurality of pulses of a number representative of the number of cells in a predetermined volume of sample liquid;

a second integrator operative in response to said plurality of pulses to provide a second analog signal of a magnitude representative of blood cell count for a predetermined volume of sample liquid;

a function generator operative in response to said second analog signal to provide a corrected analog output signal of a magnitude representative of blood cell count corrected for coincidence error;

a third linear gate operative in response to said corrected output signal and for the interval of said start signal to charge a capacitor to a voltage representative of blood cell count;

a fourth linear gate operative upon discontinuance of said start signal to provide an output signal derived from the discharge of said capacitor and defining a time interval representative of coincidence error correction;

a comparator coupled to the output of said fourth linear gate and operative to provide a gate signal of duration equal to said time interval and representative of coincidence error correction;

an oscillator for providing a plurality of correction pulses during the duration of said gate signal;

a first AND gate enabled for the duration of said start signal to pass said plurality of pulses from said divider means;

a second AND gate enabled upon termination of said start signal to pass said correction pulses; and

an OR gate for receiving said output pulses from said first AND gate and said correction pulses from said second AND gate for providing the sum of said received pulses thereby to provide a corrected plurality of pulses of a number corrected for coincidence error.

2. The system according to claim 1 further comprising:

a multiplier operative in response to said analog output signal from said first integrator and to a signal derived from said corrected plurality of pulses from said OR gate to provide an output signal representative of hematocrit.