Method and apparatus for detecting biological activities in a specimen
AssigneeBecton, Dickinson and Company
InventorKlaus W. Berndt
Life of this patent
Estimating the term…
Abstract
A pressure/vacuum method and instrument for detecting biological activities in blood culture vials, that is non-invasive, does not require chemical sensors, does not require high-brightness short-wavelength light sources, is safe against eventual extreme high pressure values, and is head-space-temperature compensated. A culture medium and blood specimen are introduced into a sealable glass vial. The normally incompressible fluid suspension is made compressible through the use of a partially inflated gas bag submerged within the medium. The changes in fluid position that result from bacterial growth related pressure changes within the vial head space are measured to detect biological activities.
Claims30
An instrument for detecting microorganisms in fluid samples, said instrument comprising:
- a sealable container containing a fluid medium and a gaseous head space above a fluid-gas interface;
- a compressible member submerged in said fluid medium within said sealable container;
- and
- means for measuring the amount of movement of said fluid-gas interface resulting from microorganism growth related pressure changes within said gaseous head space and compression of said compressible member.
An instrument for detecting microorganisms in fluid samples, said instrument comprising:
- a sealable container mounted about a pivot point containing a fluid medium and a gaseous head space above a fluid-gas interface;
- a compressible member submerged in said fluid medium within said sealable container on one side of said pivot point;
- and
- means for measuring the amount of movement of said fluid-gas interface resulting from microorganism growth related pressure changes within said gaseous head space by monitoring a torque of said sealable container.
A method for detecting pressure changes resulting from the growth of microorganisms in fluid samples, said method comprising the steps of:
- introducing a specimen into a sealable container containing a fluid medium and a gaseous head space above a fluid-gas interface;
- submerging a compressible member in said fluid medium in said sealable container;
- and
- measuring the amount of movement of said fluid-gas interface resulting from microorganism related pressure changes within said gaseous head space and compression of said compressible member.
A method for detecting pressure changes resulting from the growth of microorganisms in fluid samples, said method comprising the steps of:
- mounting a sealable container containing a fluid medium and a gaseous head space above a fluid-gas interface about a pivot point;
- submerging a compressible member in said fluid medium in said sealable container on one side of said pivot point;
- introducing a specimen into said sealable container;
- and
- monitoring a torque of said sealable container resulting from microorganism related pressure changes within said gaseous head space.
An instrument for detecting microorganisms in fluid samples, said instrument comprising:
- a sealable container containing a fluid medium and a gaseous head space above a fluid-gas interface;
- a gas bag partially filled with a compressible fluid and submerged in said fluid medium within said sealable container, wherein the density of said compressible fluid within said gas bag is substantially equal to the density of said gaseous head space;
- and
- means for measuring any change in the position of said fluid-gas interface resulting from microorganism growth related pressure changes within said gaseous head space and compression of said gas bag.
An instrument for detecting microorganisms in fluid samples, said instrument comprising:
- a sealable container containing a fluid medium and a gaseous head space above a fluid-gas interface, said sealable container being mounted about a pivot point;
- a gas bag partially filled with a compressible fluid and submerged in said fluid medium within said sealable container, wherein the density of said compressible fluid within said gas bag is substantially equal to the density of said gaseous head space and said gas bag is disposed on one side of said pivot point;
- and
- means for monitoring a torque of said sealable container, said torque of said sealable container changing if a portion of said fluid medium moves across said pivot point in response to a change of pressure within said gaseous head space.
Dependencies are inferred from the claim text.