Apparatus for evaluation of biological fluid

Abstract

The apparatus comprises a plurality of stationary cuvettes, a chamber for the fluid to be evaluated, means for placing the chamber in fluid communication with each of the cuvettes and for permitting the flow of fluid from the chamber into each of the cuvettes, a plurality of optical transmitting means in registration with each of the cuvettes for transmitting a beam of radiant energy through each of the cuvettes, and detector means for intercepting each of the beams of radiant energy and for measuring any optical changes in the radiant energy passing through the fluid in each of the cuvettes. The chamber for the fluid, the plurality of cuvettes and the fluid communication means are all housed within, preferably, a disposable, self-contained cartridge of unitary construction. The cartridge is mountable within a carriage that houses the transmitting and detector means of the apparatus. The chamber which forms the upper portion of the cartridge can be prefilled with bacterial suspension. Periodically during the growth of the subject bacteria the suspensions are agitated by suitable means. Samples of antibiotics of varying potency are placed in the cuvettes. The cartridge is mounted in the carriage. On a signal from the detector means a portion of the suspension passes into each of the cuvettes to begin the antibiotic titer which is evaluated by means of the transmitting and detector means and associated electronic circuitry.

What we claim is: 
     
       1. An apparatus which comprises: a. a plurality of .[.stationary.]. cuvettes,   b. a chamber for fluid,   c. a plurality of unidirectional valves each of which is mounted between said chamber and each of said cuvettes for placing said chamber in fluid communication with each of said cuvettes and for permitting flow of fluid from said chamber into each of said cuvettes,   d. a plurality of optical transmitting means in registration with each of said cuvettes for transmitting a beam of radiant energy through each of said cuvettes,   e. detector means for intercepting each of said beams of radiant energy passing through the fluid in each of said cuvettes,   f. pneumatic valve means operably connected between said chamber for fluid and said detector means for causing a pressure differential between said chamber and each of said cuvettes in response to a signal from said detector means for permitting flow of fluid from said chamber to each of said plurality of cuvettes, and   g. gas permeable means in gaseous fluid communication with each of said cuvettes to permit gas present in said cuvettes to escape from said cuvettes when said unidirectional valves are open and to ease the flow of fluid from said chamber to each of said plurality of cuvettes.   
     
     
       2. The apparatus of claim 1 wherein said plurality of .[.stationary.]. cuvettes and said chamber form a self-contained cartridge of unitary construction. 
     
     
       3. The apparatus of claim 2 wherein said cartridge is mountable within a carriage for housing said plurality of optical transmitting means and detector means, which cartridge contains means for placing each of said cuvettes in respective registration with said transmitting and detector means. 
     
     
       4. The apparatus of claim 3 wherein agitating means is provided for vibrating said carriage. 
     
     
       5. The apparatus of claim 3 wherein said cartridge comprises said plurality of cuvettes, said chamber mounted above said plurality of cuvettes and said unidirectional valves for placing said chamber in fluid communication with each of said cuvettes. 
     
     
       6. The apparatus of claim 5 wherein each of said unidirectional valves is mounted between the floor of said chamber and each of said cuvettes and pneumatic valve means operably connected between said cartridge and said detector means for causing a pressure differential between said chamber and each of said cuvettes in response to a signal from said detector means for permitting flow of fluid from said chamber to each of said plurality of cuvettes. 
     
     
       7. The apparatus of claim 6 wherein gas permeable means is in gaseous fluid communication with each of said cuvettes to permit gas present in said cuvettes to escape from said cartridge when said unidirectional valves are open to ease the flow of fluid from said chamber to each of said plurality of cuvettes. 
     
     
       8. The apparatus of claim 1 wherein optical transmitting means is in registration with said chamber for transmitting a beam of radiant energy through said chamber and said detector means is capable of intercepting said beam of radiant energy passing through said chamber and for measuring any optical change in said radiant energy passing through the fluid in said chamber. 
     
     
       9. The apparatus of claim 1 wherein computer means is operably connected to said detector means for analyzing the response from said detector means and for distinguishing between the optical changes taking place within the fluid in each of said cuvettes. 
     
     
       10. An apparatus which comprises: a. a plurality of .[.stationary.]. cuvettes,   b. a chamber for biological fluid mounted above said cuvettes, which chamber forms a self-contained cartridge of unitary construction with said cuvettes,   c. a plurality of unidirectional valves each of which is mounted between the floor of said chamber and each of said cuvettes for placing said chamber in fluid communication with each of said cuvettes,   d. a plurality of optical transmitting means for transmitting a beam of radiant energy through each of said cuvettes and said chamber,   e. detector means for intercepting each of said beams of radiant energy and for measuring any optical change in said radiant energy passing through the fluid in each of said cuvettes, and in said chamber,   f. a carriage for housing said plurality of optical transmitting means and said detector means, which carriage contains means for placing each of said cuvettes in respective registration with each of said transmitting means and said detector means,   g. pneumatic valve means operably connected between said cartridge and said detector means for causing a pressure differential between said chamber and each of said cuvettes in response to a signal from said detector means for permitting flow of fluid from said chamber to each of said plurality of cuvettes,   h. gas permeable means in gaseous fluid communication with each of said cuvettes to permit gas present in said cuvettes to escape from said cartridge when said unidirectional valves are open and to ease the flow of fluid from said chamber to each of said plurality of cuvettes, and   i. detection amplifier means operably connected to said detector means for amplifying the response from said detector means, filter means operably connected to said detection amplifier means for filtering out extraneous noise and baseline correction means for measuring the offset baseline values of said response prior to every reading of said detector means and for subtracting the offset baseline from the response after each reading is taken.   
     
     
       11. The apparatus of claim 10 wherein agitating means is provided for vibrating said carriage. 
     
     
       12. The apparatus of claim 10 wherein computer means is operably connected to said detector means for analyzing the response from said detector means and for distinguishing between the optical changes taking place within the fluid in each of said cuvettes. 
     
     
       13. The apparatus of claim 10 wherein program control means is operably connected to said pneumatic valve means for activating said valve means on a signal from said detector means. 
     
     
       14. The apparatus of claim 13 wherein code means is mounted on said cartridge and is operably connected to said program control means for indicating to said program control means the nature of the desired test sequence. 
     
     
       15. The apparatus of claim 12 wherein AGC means is operably connected to said detection amplifier means for providing said computer means with response levels that will enable operation of said computer means in its optimum region, sample and hold means is operably connected to said AGC means for sampling the resulting amplified response from the detection means of the first of said cuvettes which contains a blank sample and for holding this response for the time interval corresponding to the reading time for said cartridge, and AGC error detection means operably connected between said AGC means and said sample and hold means for causing the gain of said detection amplifier means to be adjusted so as to optimize the amplified response from said first cuvette containing a blank sample.