Other

Applied Medical Technology, Inc.

Sequioa Turner

Henry D Schwartz

Irwin H Krull

Frederick H Stengel

David D Hayslett

Carl J Clement

Carl P Clement

The present disclosure provides better aspiration and dispensing of fluids by an innovative mechanism by (i) offsetting the diameter of a bottom tube with a narrower top piston when the two are moved together in the same chamber to give extremely fine resolution, thereby eliminating the need for any skinny or filamentous piston, (ii) letting the bottom tube move in the chamber alone without offset to give high flow, (iii) an at-the-ready space between the tube and piston in the chamber to permit contact-free blowoff, including viscous samples, and (iv) a frame, adjustable knob and readable volume gage that let the mechanism operate as a handheld pipettor apparatus for various volumes.

Dual differential displacement fluid metering

The present disclosure provides better aspiration and dispensing of liquids by an innovative mechanism by (i) offsetting the diameter of a bottom tube with a narrower and tapered top piston when the two are moved together in the same chamber to give extremely fine resolution, thereby eliminating the need for any skinny or filamentous piston, (ii) using thick walled compliant O-rings to seal against the different diameters of the tapered piston to given an additional order of magnitude range of resolution, (iii) letting the bottom tube move in the chamber alone without offset to give high flow, and (iv) an at-the-ready space between the tube and piston in the chamber to permit contact-free blowoff, including viscous samples.

Dual resolution liquid handling

The present disclosure provides better aspiration and dispensing by a common innovative mechanism by (i) offsetting the diameter of a bottom piston (tube) with a slightly narrower top piston (rod) when the two are swept together by O-rings to give extremely fine resolution, thereby eliminating the need for any filamentous piston and sealing means, (ii) letting the bottom tube be swept alone without offset to give high flow (iii) using a tapered top rod with thick-walled compliant O-ring seals to increase the resolution multiplier another order or magnitude, (iv) an at-the-ready interpiston space for contact-free blowoff, including viscous samples, (v) dead space filler mandrels and an integrated small valve to reduce or eliminate interpiston and disposable tip space prior to aspiration, and (vi) a mechanism for storing energy during disposable tip pickup to shoot dispensed samples contact-free down into long tubes.

Core pipetting mechanism and method

The testing apparatus is for measurement of ions in body fluids. The apparatus has a plurality of sample cups for containing fluids to be tested, a movable door for controlling access to the sample cups, and a plurality of measuring electrodes for immersion into the fluid to be tested. There is a hand operated device for moving the electrodes and the cups with respect to each other to alternately put the electrodes in a first position permitting access to the cups and in a second position in which the electrodes are immersed in the fluids to be tested contained in the cups. Means for mounting the cups in the testing apparatus are engaged with means for oscillating the cups independently of the electrodes. The oscillation fully exposes the electrodes to a representative sampling of the fluids within the cups and thus enhances the accuracy of the test being performed. The method is for the measurement of chlorides, ionized calcium, sodium and potassium as well as other ions in fluids obtained from the body or elsewhere. The method includes the step of using the controlled oscillation of a small sample fluid in direct contact with an electrode, to thoroughly expose a true representative sample to the electrode for measurement.

Sample container for measurement of ions of body fluids

Testing apparatus for measuring ions in fluids

The testing apparatus is preferably for the measurement of ionized calcium and other ions in biologic fluids. The apparatus generally comprises a turntable that is incrementally operated, a cover overlying the turntable, a housing for supporting the turntable and cover and a plurality of sample cups carried by the turntable. At one area of the cover there is defined a probe station having means supporting a plurality of probes which sample the fluid in the cups and generate electrical signal responsive to sensed ions which signal may be a high impedance signal. The electrical signal is coupled preferably via a coaxial cable to a relay device and from thence to an electrometer external of the apparatus. The relay device and other electrical or conductive components are isolated from chassis ground to improve signal transmission. A special shield dome covers the turntable, cover and probe assembly and this shield dome is the only part above the housing that is grounded. The dome has a lower position resting on the housing top and an upper position which permits access to the turntable. The dome is transparent as are the individual probes.

Clinical testing apparatus

The testing apparatus is preferably for the measurement of ionized calcium and other ions in biologic fluids. The apparatus comprises a selectively operated turntable defined by a plurality of radially extending leaves fixed in position at one end along a circular locus, a cover overlying the turntable, and a plurality of sample cups carried by the turntable and each received by and positioned at the free end of one of the leaves. The leaves flex sufficiently to provide a bias on the cup urging the top edge of the cup into intimate contact with the bottom surface of the cover. The cover is at least partially hollow forming a plenum chamber for a saturated gas such as carbon dioxide and having a number of outlet jets spaced along a circumference of the cover with each jet for directing a flow of the gas into the cup at a suitable velocity to produce a good mixing and swirling action in the cup. In addition to the plenum mixing holes there is also an independent mixing hole at the probe station where a probe assembly comprising one or more probes is selectively and sequentially registered with the cups. The cover may also be provided with one or more sensor holes disposed outside of the mixing hole at the probe station. One sensor hole may have means associated therewith to permit introduction of an alternative gas to the cup at the probe station when this hole is blocked by a cup of special shape having a larger outside diameter. The other sensor hole may have means associated therewith to identify the cup at the probe station as containing a particular type of sample. By selection of the proper configuration of cup one can effectively program operation of the apparatus.

Clinical testing means for determining pH dependent body fluid substances. In vivo ionized calcium concentration is obtained by withdrawing a blood specimen, determining the pH of the serum when withdrawn from the body and later, determining the in vivo ionized calcium concentration at the original pH. The pH of the serum is adjusted to the original pH by equilibration with carbon dioxide after which the ionized calcium concentration is directly electrically measured. Alternately, the original ionized calcium concentration is extrapolated or interpolated by making two different pH adjustments, electrically measuring calcium ion concentration, graphing the points obtained on semi-log paper to form a straight line graph from which the original calcium ion concentration can be obtained knowing the original serum pH. In still another variation, an extrapolation can be made to determine the carbon dioxide adjustment required to produce the original pH, after which pH adjustment the original concentration can be directly measured. Other variations of the methods are used to obtain less reliable but useful ionized calcium concentrations. A relationship between ionized calcium and total calcium in serum is used to determine total calcium levels. Multiple sample serum testing means has a rotatable sample container turntable and a cover means through which carbon dioxide can be simultaneously introduced into plural samples. The sampling means carries pH determining means and ionized calcium determining means for rapid ionized calcium measurements.

Growing community of inventors

Palo Alto, CA, United States of America

Henry D Schwartz