CONSTANT TEMPERATURE TRAY FOR STORAGE OF BIOLOGICAL SAMPLES

Abstract: Constant temperature receptacle (2) for storage of containers of biological samples. The receptacle's ability to maintain a constant temperature is based upon effective heat exchange between such containers and high thermal capacity medium in contact with the contoured surface element (2A) which cradles the containers of biological samples. Additional features of this receptacle include an insulating base (4) for isolation of the high thermal capacity medium from the ambient environment and a flexible cover (6) adapted for engagement with an disengagement from the tray portion of the receptacle; thus, protecting its contents from exposure to contaminants and ambient temperatures.

Description: CONSTANT TEMPERATURE TRAY FOR STORAGE OF BIOLOGICAL SAMPLES DESCRIPTION OF THE PRIOR ART Field of the Invention - This invention is directed to an article of manufacture. More specifically, this invention concerns itself with a constant temperature receptacle adapted for short-term storage of containers of biological samples. Description of the Prior Art - Arterial blood for diagnostic testing in blood gas analyzers is commonly collectd by means of syringes, vacuum tubes or capillary tubes. In order to insure more accurate and consistent results in performing such blood gas analysis, it is essential to minimize sample handling, exposure of the sample to air and exposure of the sample to conditions which would alter the solubility of the gas in the specimen. U.S. Patent 4,263,922 describes means for effectively collecting arterial blood samples consistent with the objectives of reproducibility and accuracy of analysis. In brief, the subject invention described in the '922 patent involves a device which utilizes a capillary tube, an adaptor-handle attachment connected to the tube and a hypodermic needle detachably mounted to the adaptor handle. Blood is collected by the phlebotomist in the usual fashion in the capillary tube by means of such device and the tube then separated from the handle and the needle. The tube can thereupon be inserted directly into a blood gas analyzer and analysis of the specimen performed without exposure of the sample to air or excessive manipulation. As is readily appreciated, the hospital routine ordinarily involves a collection of numerous samples and the subsequent forwarding of the samples to the clinical laboratory at some point in time subsequent to their collection. If the interval between collection and analysis of the sample exceeds permissible storage time at normal temperatures or the conditions in the hospital are inconsistent with prolonged storage of the sample, the solubility of gases in the blood will be effected and, thus, subsequent analysis performed on the sample ' will not provide a true and accurate profile of the gases in the patient's blood. It is thus apparent that in order to insure that the analysis on the patient's sample accurately re lect the concentration of the gases in his blood that such analysis of the sample should either be done as soon as practical after collection of the sample or that the sample be isolated from the 10 ambient environment in order to effectively prevent significant changes in the solubility of the gas within the blood. SUMMARY OF THE INVENTION • j r Accordingly, it is the object of this invention to remedy the above as well as related deficiencies in prior art systems for collection of biological s.amples. More specifically, it is the principal object of this invention to provide a constant temperature receptacle for the short-term storage of containers 20 of biological samples. • It is yet another object of this invention to provide a receptacle for the _ > short-term storage of containers of biological samples which effectively isolates the containers from contamination by the ambient environment. 25 It is still yet another object of this invention to provide a constant temperature receptacle for the short-term storage of blood gas tubes and the instruments associated with collection of the blood in such tubes. 30 The above and -related objects are achieved by providing a constant temperature receptacle adapted for the short-term storage of containers of biological samples which includes a tray of thin walled construction having a base portion and a contoured upper surface portion. The interior surface walls of each portion of the tray collectively form an interior chamber which 35 is adapted for the receipt and storage of a high thermal capacity medium. The interior chamber of this tray is essentially filled to capacity in order to insure virtual contact of the high thermal capacity medium with each of the contours of the upper surface portion of the tray. In addition, the base portion of the tray is cradled or fitted to an insulating member (i.e., an expanded polymeric foam) and the upper portion of the tray covered by a removable enclosure which is adapted for engagement/disengagement of the upper portion of the tray. The contoured portion of the upper portion of the tray is designed for maximum surface contact between the containers of biological samples and the surface of the tray in order to provide effective heat transfer therebetween. In addition, the surface contours of the tray may also be molded to retain instruments or components of instruments which are used in the collection of the biological samples. In one of the preferred embodiments of this invention, the insulating member and the base portion of the tray will be in essentially virtual contact, 'thus eliminating any air spaces between the two. In another of the preferred emboidments of this invention, the cover portion of the tray is also prepared from an insulating material and such insulating material need not be the same as that surrounding the base of the tray. f BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is an elevation view from above of the constant temperature receptacle of this invention. Fig. 2 is a cross-sectional view of the constant temperature receptacle. Fig. 3 is an enlargement of the contours of a portion of a cross-section of the receptacle which is illustrated in Fig. 2. Figs, h and B are an enlargement of a cross-sectional view through the cover of the tray during its engagement with ( A) and disengagement from ( B) the edges of the tray. 5 DESCRIPTION OF THE INVENTION INCLUDING THE PREFERRED EMBODIMENTS The following description of the drawings is intended to be illustrative 10 of preferred embodiments of this invention and therefore simply to provide for a better understanding thereof and not delineation of its scope. Referring now to Fig. 1, in which is illustrated a representative configuration of a constant temperature receptacle having a contoured tray j zj component 2 nesting in an insulating base 4. The contoured surface component 2a of the tray is laminated to a base 2b along its outmost edge in the manner illustrated in Fig. 2. The contoured surface and base portions of the tray, in this embodiment of the invention, are formed rom essentially the same materials and fused to one another at their contiguous edge. Their combination in this manner forms reservoir 8 which is suitable for storage 20 and retention of a high thermal capacity medium (not shown). The contoured surface portion of tray and the base need not necessarily be formed from the same materials nor need the contoured surface portion of the tray or base be formed separately. For example, the contoured surface portion and the base can be formed simultaneously by blow molding or injection molding 25 techniques, thus, simplifying their assembly. Once the reservoir is formed by these two elements of the tray, a high thermal capacity medium is injected into the reservoir through aperture 10. Upon essentially complete filling of the reservoir with the high thermal capacity medium, the aperture can be sealed with a plug or other suitable means. 30 In a typical embodiment of this invention illustrated in Fig. 3, the contoured surface portion of the tray, provides sufficient contact between the surface of the tray 16 and the container of the biological sample 12 to effectively maintain the temperature of the specimen 14 within the container 35 12 so as to insure sufficient stability of the sample thus preserving the integrity and concentration of the analyte of interest within the sample. In addition to the contours which are designed to conform to at least a substantial portion of the container of the biologic sample, other contours 16, IS and 20 can also be provided for retention of instruments and/or other accessory implements needed in the collection of the biological sample/specimen. In the embodiment of this invention which is illustrated in the drawing, the specimen container is a microcapillary tube of the type described in U.S. Patent 4,266,922. As is readily appreciated, the length and proportions of the contours of the tray are tailored in advance to conform with the container of the biological sample. As noted previously, it is not necessary for the tray contour to be in contact with the entire surface of the container of the biological sample so long as substantial contact is maintained and such ' . , contact is sufficient to provide adequate heat exchange . between the container of the biological sample and the high thermal capacity medium which fills the reservoir below the contoured surface portion of the tray. In order to isolate the containers of biological samples from contamination by the ambient environment, the tray is also provided with cover 6. This cover can be slidably mounted to enclose the contoured surface of tray be engaging the sides of the tray at edges 40. A stop (not shown) is _ present at the end of the cover so as to effectively seal the area below the cover from the ambient environment and yet permit the tray to be removed by sliding it in the direction of the stop. AS shown in Figs. 4A and 4B, the edge of the tray engages the cover at 40 in the crowned configuration and disengages the sides of the tray upon compression at 42. In the compressed mode, the cover can be readily removed by simply sliding it toward one end of the tray or the other (depending upon the position of the stop relative to the end of the cover). The insulating base component 4 of a receptacle can be formed around the base portion of the tray or preformed. Preferrably, the insulating component 4 of the tray is composed of a polymeric foam material and the base portion of the tray nests within the insulating member to the total exclusion of air therebetween. OMPI The high thermal capacity medium 20 which is contained within reservoir 8 (formed by the contoured portion and base portion of the tray) can be virtually any material which experiences a phase change between the extremes of temperature contemplated in its use (i.e., -IOC to room 10 temperature); and preferrably at or slightly below room temperature ( 18- 20C). Typically, such material will be a high viscosity fluid under ambient conditions and can thus be readiy dispensed through aperture 20 of the tray into the reservoir 8. Upon chilling of the tray, the high viscosity fluid will undergo a phase change upon cooling, forming a thixotropic gel-like material. i Presumably, this phase change could be achieved by simply storing the ■ . ^ receptacle in a refrigerator or freezer compartment overnight prior to its use by a phlebotomist the following day. Then, upon removal from the refrigerator, the cooling material retains the tray at constant, low temperature for an extended time interval until, all the material has returned to the liquid phase, as would, for example, ice cubes in equilibrium with 20 water. Typical of the materials which are suitable as high thermal capacity media include the "eutectic gels" available from Jack Frost Laboratories (Fort Pierce, Florida). In addition to the embodiments of this invention which are specifically 25 illustrated and described heretofore, it is apparent to those skilled in the art that variations or modifications can be made thereto which are within the spirit of this invention and the scope of the claims which follow: 30 35 OMPI

Claims: WHAT IS CLAIMED IS 1. A constant temperature receptacle adapted for short term storage of containers of biological samples, comprising: (a) a tray of thin walled construction having a base portion and contoured upper surface portion, the interior surfaces of the walls of each such portion collectively defining an interior chamber for containment of a high heat capacity medium in essentially virtual contact with the contoured upper surface portion thereof; (b) an insulating member fitted to at least the base portion of such tray; (c) a removable cover adapted to isolate the contoured surface of the tray from contamination by the environment and adapted for engagement and disengagement to the contoured upper portion of said tray; and (d) a high thermal capacity medium essentially completely filling the interior chamber defined by the interior surfaces of the contoured and base portion of the tray. r 2. A receptacle of claim 1, wherein the contoured upper surface portion of the tray provides for substantial contact between the surface of the tray and the surface of the containers of biological samples. 3. A receptacle of claim 1, wherein the cover comprises a transparent elongated dome which is adapted for engagement of the upper surface portion of the tray and upon compression of said dome, for the disengagement thereof. 4. A receptacle of claim 1, wherein the insulating member comprises a foamed polymeric material. 5. A receptacle of claim 1, wherein the high thermal capacity medium undergoes a phase change within the temperature range of from about - IOC to about 20C. OM 6. A receptacle of claim 1, wherein the tray is a unitary structure. 7. A receptacle of claim 1, wherein the tray is of composite construction and components thereof assembled subsequent to formation of each component. 8. A receptacle of claim 1, wherein the components of the tray are assembled by fusion to one another along their contiguous surfaces. 9. A receptacle of claim 1, wherein the insulating member and base portion of the tray are in essentially virtual contact. 10. A receptacle of claim 1, wherein a second insulating member is fitted to the upper surface portion of the tray and serves as its cover. 11. A receptacle of claim 1, wherein the second insulating member comprises a material which is distinct from the insulating material of the insulating member. r 12. A receptacle of claim 1, wherein the contoured upper portion of the tray is provided with accessory recesses for implements used in the collection of biological samples.

Inventors: WHITE FRED K, WHITE, FRED, K.
Applicants: AMERICAN HOSPITAL SUPPLY CORP, AMERICAN HOSPITAL SUPPLY CORPORATION
Application year: 1982
Main classification: F25D3
IPC codes: B01L7, F25D3