US 3219421 A
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Description (OCR text may contain errors)
Nov. 23, 1965 R. SCHWARZ, JR.. ETAL 3,219,421
TUBE FOR USE IN DIAGNOSTIC AND THERAPY CONTROL Original Filed March 20, 1963 lNVENTORS ATTORNE United States Patent Office 3,219,421 Patented Nov. 23, 1965 3,219,421 TUBE FOR USE IN DIAGNOSTIC AND THERAPY CONTROL Robert Schwarz, Jr., Tenafly, and Helmut G. Tietje, Westwood, NJ. Continuation of application Ser. No. 266,587, Mar. 20, 1963. This application Jan. 18, 1965, Ser. No. 426,095 2 Claims. ((31. 23292) This application constitutes a continuation of application Serial No. 266,587, filed March 20, 1963, which is a continuation-impart of application Serial No. 188,357, filed April 18, 1962, both now abandoned.
The present invention relates to an improved tube construction for diagnostic and therapy control applications, and more particularly, to a tube of this nature facilitating the expeditious identification of the tube contents.
In clinical as well as laboratory practice, samples of materials to be tested are frequently placed in tubes, vials or similar vessels and receptacles, In this connection, various controls and reagents are similarly contained as part of the diagnosis and particular therapy under consideration. The particular tube contents may then be placed through at least one of a series of tests and may even have samples thereof extracted or aspirated and mixed as part of the test procedure. Quite obviously, if the tubes are not properly identified, their contents and the samples thereof may not be properly employed, thereby enhancing the possibility of obtaining erroneous test results. The consequences could be extremely confusing, if not damaging and detrimental.
For example, the tubes may be utilized in prothrombin and coagulation time determinations wherein standardized and stabilized chemical reagents are placed in such tubes and heated to selected operating temperatures, approximately that of the normal human body. The quantity of reagent is ordinarily fixed for proper time determinations. Control plasma of predetermined quantity, also in such tubes, is then dispensed in one of the tubes containing a reagent. A probe, either manually or automatically operated, is then inserted and withdrawn from this tube for purposes of sensing the initial clot formation. The same procedure is followed utilizing a controlled amount of patients plasma. The prothrombin times are read and recorded. If the tubes and their contents are not clearly identified, confusion is likely to ensue; and inaccurate results are inevitable, particularly in view of the critical nature of time in such investigations. This environment as well as application of the tube of this invention is disclosed in detail in application Serial No. 188,934 filed April 18, 1962.
It is, therefore, a primary object of this invention to provide a structurally improved tube for use in diagnostic and therapeutic work, having means for receiving indicia readily viewable by the diagnostician or clinical attendant.
The present invention contemplates essentially a tube of standard volumetric capacity closed at one end and open at the other. A radial flange extends integrally from the open end of the tube and is so constructed and arranged to provide a relatively enlarged surface area. This area is so conditioned to permit the reception of the desired indicia. Under these circumstances, the tube and its ultimate contents are most expeditiously identified; and their possible erroneous use and misapplication of test samples of the tube contents effectively minimized, if not eliminated, In addition, tube dimensioning and materials for tube fabrication are selected to assure accurate prothrombin time determinations because of optimum volumetric control and heat transfer.
Other objects and advantages will become apparent from the following detailed description which is to be taken in connection with the accompanying drawing illustrating a somewhat preferred embodiment of the invention, in which:
FIG. 1 is a top perspective View of the tube embodying the teachings of the present invention shown associated with another identical tube both of which are mounted in a heating block fragmentarily illustrated;
FIG. 2 is an enlarged top plan view thereof; and
FIG. 3 is a longitudinal sectional view taken along the line 33 of FIG. 2.
In the drawings, a tube 10 of any desired volumetric capacity will be formed with the usual cylindrical side wall 12 having a bottom closed end 14 and opened upper end 16. In this connection, it has been found desirable to provide the tube 10 with standard volumetric capacities which, for example, may be in the nature of a few tenths of a milliliter. This size tube would have particular application to prothrombin and coagulation time determinations. The materials utilized in fabricating the tube 10 may be any one of a number of resins or plastics possessing characteristics and properties desirable for the selected tube applications and uses. With this in mind, the tube 10 is preferably of a disposable nature such that, after a particular single use, it may be discarded thereby eliminating the need for cleansing and sterilization. It should be understood, however, that materials lending themselves to permanent use and the various sterilization techniques are also embraced by this invention. A successful and somewhat preferable application of this invention embraces those dimensions and materials specifically set forth below.
Since it is particularly important to incorporate conveniently located indicia receiving means, the tube 10 is formed with a flange 18 extending radially outwardly from the open end 16. This flange is advantageously enlarged to provide an elongated radial strip 20 having an enlarged upper face 22. The desired indicia can be conveniently placed on this surface so that it can be readily viewed. Thus, the top face 22 may be defined by a pair of spaced and substantially parallel side edges 24 and 26 extending tangentially from the periphery 28 of flange 18. The terminal ends of the periphery edges 24 and 26 are connected by an annular side edge 30 to provide the top of the tube 10 with a somewhat symmetrical appearance. Under these circumstances, the upper face 22 of the strip 20 will provide suflicient area for the reception of the selected indicia.
In order to expedite the placement of indicia on the strip 20, a zone 32 of the upper face may be treated either chemically or mechanically to provide a roughened surface on which writing may be inscribed as, for example, with an ordinary pencil or pen. On the other hand, the zone 32 for writing may be the result of the molding process employed. It has been found that satisfactory results are obtainable by providing zone 32 with the desired properties and characteristics through frosting, sand blasting and the like techniques. In any event,
in order to provide a symmetrical and neat appearance, particularly when viewing the strip 20 and its upper face 22, the zone 32 may be defined by a pair of spaced and parallel edges 34 and 36 extending tangentially from the inner face of the top end 16. The edge 30 of the strip 20 may define the remaining side of the zone 32.
Thus, in assuring accurate application of the tube and its contents to the particular diagnostic and therapeutic determinations, the desired indicia, which may be inscribed, marked or in any other discernable media readilyidentifiable, need only be placed or written on the upper face 22 of the strip 20. In this connection, an adhesively coated strip or tape can be applied to the upper face 22 and bear the desired data. Quite obviously, other data can be similarly placed or written from time to time in lieu of or in addition to the original. Of importance is the fact that the strip does not detrimentally affect the handling of the tube 10, nor render it cumbersome in filling or removing any of the tube contents. In fact, provisions for the strip 20 in accordance with the present invention eliminates marking of the body 12 of the tube 10 with either written material or adhesively backed tape. Under such circumstances,
the tube contents would from time to time be hidden from view and certainly not be clearly viewable through the entire length of the tube. Tape would also interfere with fit in heating block which would interfere with heat transmission and might make insertion impossible or might prevent seating which is required for automatic determination of prothrombin time, for example.
In arriving at the dimensioning of the tube 10, the following criteria should be considered:
(a) The length of strip 20 should be sufliciently long to permit manual gripping thereof as well as adequate room for labelling; and the strip should not be unduly lengthened thereby resulting in occlusion of the openings of adjacent tubes or prevention of seating of the subject tube or prevention of insertion of adjacent tubes.
(b) The thickness of the side wall 12 should be selected to avoid providing undesirable flexibility; and the thickness should not be increased beyond that point at which heat conduction therethrough will be decreasedsignificantly thereby resulting in inconveniently long solution warm-up times.
(c) The outer diameter of the tube side wall 12, together with that of the bottom closed end 14, should be selected such that it is not too large thereby making proper seating of the tube in the well of a heating block, for example, extremely difiicult if not impossible; and if this outer diameter is too small, particularly in relation to this well, proper heat transmission into the tube contents will be detrimentally affected.
(d) The inner diameter of the tube side wall 12 and bottom closed end 14, if too small, will raise liquid level to an extent whereby a clot will be registered by a coagulation timer, of the type disclosed in application Serial No. 188,934 filed April 18, 1962, through the level of the liquid even without formation of a clot; and if this dimension is too large, the liquid level in the tube will be lowered to a point at which the clot will not be picked up and sensed. Value of the internal diameter specifically disclosed below is important for the following reasons:
(1) that if narrower, the sensitivity to pipetting error will be excessive and there will be an increase in the criticality of the distance between the upper surface of the liquid in the tube and the sensing probe of the above mentioned coagulation timer; and
(2) that if wider, the upper surface area of the tube contents will be increased to the extent that evaporation and heat loss may give rise to problems afifecting accuracy of prothrombin times; and the portion of the vertical section of the liquid swept through by the sensing probe will be decreased to the extent that the factor of missing a clot will be introduced.
(e) The outer surface of the side wall 12 and closed bottom end 14 should be sufficiently smooth to insure adequate heat transmission from well to tube; and the inner surface should 'be smooth to insure that the tube contents are adequately mixed.
A successful application of the tube of this invention embraced the following dimensioning.
Tube bottom end 14:
Inner radius 1943.001"
Outer radius 2221.001 Tube side wall 12:
Thickness .028 .002
Taper (outwardly to open end) 130'il0' Tube height .750i.0l0" Strip 20:
A preferred material from which the tube of this invention is fabricated because of its superior dimensional suitability and optimum heat transfer characteristics is high density polyethylene. In this connection, this material provided for heat transmission through the tube from the well to the tube contents in a minimum period of time. In addition, tube shrinkage was significantly minimized, if not eliminated, and acceptable matching or meeting relationship between tube and well was attained in substantially all instances. Consequently, errors in prothrombin time determinations were reduced.
It should, therefore, be understood that the aforenoted objects and advantages, among others, are most effectively attained. Although a single somewhat preferred embodiment of this invention has been disclosed and described in detail herein, the invention is not in any sense limited thereby, and its scope is to be determined by that of the appended claims.
1. A disposable tube having ability for obtaining optimum liquid level and heat transfer characteristics and being of standard volumetric capacity for containing a liquid sample in the order of tenths of a milliliter for use in diagnostic and therapy control in prothrombin time determinations made in a coagulation timer which are carried out at body temperatures within said tube, said tube being formed of molded synthetic resin suitable for coagulation tests and having suitable heat transfer characteristics, said tube having an open top end and a closed bottom end, the tube having a circular cross section substantially throughout its length, the interior and exterior surfaces of the tube being substantially smooth, the length of said tube being larger than its internal diameter and the closed bottom of said tube being hemispherical in configuration, the open end of said tube being provided with a flange extending radially outwardly of the tube, said flange having a substantially semi-circular peripheral edge, a strip projecting radially from the tube open end in the form of an integral extension for permitting manual holding of the tube, said strip having a pair of spaced side edges extending substantially tangentially from the peripheral edge, said strip having 29. length and width which cooperate together in providing a surface area sufficient for reception of selected indicia, the resin and thickness being selected such that the tube is provided with minimum flexibility and maintains its shape under test conditions at approximately body temperatures and provides suitable heat conductivity during warmup of the liquid contents of the tube and during the coagulation tests, the inner radius of the tube permitting vertical manipulation of a probe into and out of the liquid so as to sense a clot, the tube tapering outwardly from the closed end to the open end, the tapering and the outer radius of the tube being selected to provide op timum contact with the heat source.
2. The invention in accordance with claim 1 wherein the molded synthetic resin consists of high density polyethylene.
References Cited by the Examiner UNITED STATES PATENTS 2,346,261 4/1944 Kamlet 23292 2,837,055 6/1958 Whitehead 16784.5 X
6 3,068,855 12/1962 Furlong 23-230 X 3,071,316 1/1963 Piemonte et a1. 23-292 X 3,115,460 12/1963 McCormick 23292 X OTHER REFERENCES Modern Laboratory Appliances, Fisher Scientific Co. Catalog 59, pp. 104 and 195 (1958), Fisher Scientific Co., New York, N.Y.
MORRIS O. WOLK, Primary Examiner.