US 3814522 A
A tube and method particularly useful in urinalysis and other analytical procedures in which the sediment in a sample of body fluid is subjected to microscopic examination. The tube is transparent, open at its upper end, and suitable for use in a centrifuge. The closed lower end of the tube is flattened to define a reduced chamber portion for retaining only a thin layer of sample, thereby permitting microscopic examination of the sediment within the flattened portion. The main body portion of the tube is provided with a flat surface extending along a plane parallel with the tube's flattened lower end portion.
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Description (OCR text may contain errors)
United States Patent Clark et al. 1 June 4, 1974 1 SPECIMEN TUBE FOR MICROSCOPIC 3.481.712 12/1969 BCfilSlCiflCl 111 350/92 EXAMINATION 3.556.633 l/l97l Motschmann ct all. 350/95 3.7l3.775 l/l973 Schmitz 356/l97  Inventors: John A. Clark, Fort Lauderdalc;
warren Wells Mlamlboth of Primary E.ran1iner--Vincent P. McGraw Attorney, Agent, or Firm-Dawson, Tilton, Fallon &  Assignee: American Hospital Supply Lungmus Corporation, Evanston. Ill.  Filed: Feb. 28, 1973  ABSTRACT A tube and method part1cularly useful 1n urinalysis Appl- N05 3361511 and other analytical procedures in which the sediment in a sample of body fluid is subjected to microscopic 52] 11.5. C1 356/197, 350/95, 356/246 examination The tube is transparent, Open at its [511 1111.01. G0ln 21/24, 0011] 1/10 upper end, and Suitable for use in a centrifuge The  of Search H 356/197 350/92, closed lower end of the tube is flattened to define a 23/292; 233/26 reduced chamber portion for retaining only a thin layer of sample, thereby permitting microscopic exam-  References Cited ination of the sediment within the flattened portion. UNITED STATES PATENTS I ghe mam body pornon of the tube 1s prov1ded w1th a at surface extend ng along a plane parallel w1th the 43l.l32 7/l89() Warton 4. 23/292 tubers flattened lower end portion- 2,817,970 l2/l957 Whitby 3.170.838 2/1965 Archer 233/26 9 Claims, 8 Drawing Figures PATENTEDJUH 419M M. MN mum l SPECIMEN TUBE FOR MICROSCOPIC EXAMINATION BACKGROUND The microscopic examination of sediment in a fluid is a standard procedure in urinalysis but might also be performed in connection with other types of laboratory tests. As is well known, urinalysis is important as a screening procedure and as an aid in differential diagnosis, and the microscopic examination of urinary sediment is a basic part of the total urinalysis procedure. Depsite the need for exercising a high degree of care in performing such examinations, errors nevertheless occur, sometimes through carelessness, in the transfer of the sediment from centrifuge tubes to microscopic slides, or in the undesirable drying of the sediment upon the slides, or in properly correlating the specimens (multiple specimens from different patients are often placed on the same slide) with the patients from whom they were obtained. Furthermore, the standard procedure tends to be time consuming because of the manipulative steps in first mixing the sediment with a small amount of supernatant so that the sediment may be transferred to a microscope slide, and then pipetting the mixed sediment to such a slide. Of at least equal im portance is the fact that such mixing and transferring steps, to the extent that they involve three items of laboratory equipment in direct contact with the sediment (centrifuge tube, pipette, and microscope slide), increase the risk of specimen contamination before the actual examination isundertaken.
SUMMARY The present invention is concerned with a device and method for overcoming the major shortcomings of current procedures as described above. Specifically, the invention is concerned with a centrifuge tube construction and its method of use which eliminate the mixing and transferring steps required under prior procedures. As applied'to urinalysis, the invention gives rise to a relatively fast clinical procedure which tends to produce more dependable results because it eliminates manipulative steps that might be performed differently by different technicians (or by the same technician on different occasions), and which also reduces the risks of contamination and possible error arising therefrom.
The device comprises a tube having an upper body portion and an integral lower end portion. The lower end portion of the tube is flattened along a plane generally Parallel with the axis of the tube to provide a pair of substantially parallel transparent walls or windows which define a flat terminal chamber therebetween. The body portion of the specimen tube defines a main chamber which communicates directly with the terminal chamber. Therefore, when the tube and its contents are centrifuged, particulate matter in the sample will be forced into the terminal chamber at the tubes lower end.
The main body of the tube is provided with a flat side surface portion, the flat surface extending along a plane substantially parallel with the plane of the tubes flattened lower end portion. Therefore, immediately following centrifugation and the decanting of the supernatant, the tube may be placed upon a microscope stage, the flat side of the tube resting upon the stage and the sediment in the terminal chamber extending in a plane normal to the line of sight through the microscope. The tube therefore performs the function of a microscope slide without requiring transfer of the sediment following centrifugation and the risks of contamination that such transfer would involve.
.THE DRAWINGS FIG. 1 is a perspective view of a specimen tube embodying the present invention;
FIG. 2 is a sideelevational view of-the tube;
FIG. 3 is another side elevational view'of the tube. taken along line 3-3 of FIG. I;
FIG. 4 is an enlarged cross sectional view taken along line 44 of FIG. 2;
FIG. Sis an enlarged cross sectional view taken along line 5-5 of FIG. 2;
FIGS. 6, 7, and 8 illustrate successive steps in the method of performing the present invention.
DESCRIPTION The numeral 10 generally designates a specimen tube embodying the invention, the tube having an enlarged upper body portion 11 and a reduced lower end portion 12. It will be observed that the body portion assumes the major portion of the length of the tube. While the size of the tube may be varied, depending on the test and the equipment with which it is to be used, the dimensions must be such that the tube is capable of being supported in a laboratory centrifuge.
The upper'body portion and lower end portion are integrally formed of glass although other materials such as transparent plastic might conceivably be used. At its top, the tube is provided with an opening 13, the opposite lower end 14 of the tube being closed as shown in FIG. 1. Lower end portion 12 is flattened along a plane generally parallel with the axis of the tube to provide a pair of flat or planar transparent walls 15 and 16 which define a thin, flat terminal chamber 17 therebetween (FIG. 5). In general, the distance between the inside surfaces of walls 15 and 16 should be uniform and should fall within the general range of 0.2 to 2.0 millimeters. A preferred range has been found to be approximately l.0 to 1.5 millimeters. As shown in FIGS. 35, the width of the terminal chamber is approximately the same as the maximum internal cross section of the main chamber 18.
Body portion 11 has a main chamber 18 communicating directly with the terminal chamber 17. The body portion may be generally cylindrical in shape (as shown) except that it is provided with at least one flattened external surface 19. It is to be noted that planar surface 19 is parallel with the axis of the tube and, of particular importance, is substantially parallel with the plane of the tubes flattened lower end portion 12. Therefore, the tube will remain stable when laid upon its flat side. If the supporting surface is a microscope stage 20 (FIG. 8), the tube may be positioned in stable condition upon that stage with the line of sight 21 (and line of illumination) of the microscope extending through the flattened terminal portion 12 and normal to the plane of that terminal portion.
Surface 19 may be roughened or etched by sandblasting or by any other suitable means. Such roughening of the surface helps to retain the tube in a selected position upon a supporting surface and, in addition, provides a surface upon which a laboratory technician may write identification symbols or other indicia. Since the main body portion constitutes by far the greater portion of the bulk or mass of the tube, there is no tendency for the tube to tip out of the stable position illustrated in H6. 8 even whenthe main chamber 18 is empty and the terminal chamber 17 contains sediment or a sediment-liquid mixture. However, in mounting the tube upon a microscope stage, it is contemplated that some clamping or supporting means (not shown) might be used to insure against relative movement of the tube during microscopic examination of its contents.
ln carrying out the method of the invention, a technician simply pipettesa liquid specimen 22 containing particulate matter 23 into the tube (FIG. 6) and the tube is then centrifuged to force the sediment into terminal chamber 17 (FIG. 7). The supernatant fluid is then poured off and the tube is placed in horizontal condition on a microscope stage 20 as shown in FIG. 8. Microscopic examination of the sediment therefore takes place immediately following the centrifuging and decanting steps, without the use of microscope slides or any of the manipulative steps required in the past. Because of its inexpensive construction, the tube may be discarded immediately following use, thereby avoiding the problems of contamination and expense which cleaning and reuse might present.
While in the foregoing we have disclosed an embodiment of the invention in considerable detail for purposes of illustration, it will be understood by those skilled in the art that many of such details may be varied without departing from the spirit and scope of the invention.
1. A specimen tube having an upper body portion and an integral lower end portion, said lower end portion being flattened along a plane generally parallel with the axis of said tube to provide a pair of substantially parallel transparent walls spaced slightly apart to define a thin flat terminal chamber therebetween, said body portion defining a main chamber communicating directly with said terminal chamber and having an enlarged flat outer surface portion substantially parallel with the plane of said flattened lower end portion, said flat outer surface portion being spaced from the axis of said tube a distance substantially greater than the distance between said axis and each of said parallel transparent walls of said terminal chamber.
2. The structure of claim 1 in which said terminal chamber is of substantially uniform thickness throughout its entireextent.
3. The structure of claim 2 in which said thickness falls within the range of about 0.2 to 2.0 millimeters.
4. The structure of claim 3 in which said thickness falls within the range of about- 1.0 to 1.5 millimeters.
5. The structure of claim 1 in which said tube is open at its upper end.
6. The structure of claim 1 in which said upper body internal cross sectional dimension of said upper body portion.
8. The structure of claim 1 in which said flat surface is roughened. 9. A method for analyzing the sediment in a body of fluid, comprising the steps of placing a quantity of said fluid into a tube closed at its lower end. said tube having a lower end portion with transparent and substantially parallel side walls spaced slightly apart to define a thin flat terminal chamber therebetween and having an enlarged upper end portion with a flat outer surface parallel with said side walls and spaced farther from the axis of said tube than said side walls, centrifuging said tube and its contents to direct said sediment into said terminal chamber, then removing the supernatant fluid from said tube, then turning said tube so that its axis extends horizontally and resting the flat surface thereof upon a microscope stage so that the line of sight of the microscope passes through said flat terminal chamber and is substantially normal to the plane of said chamber, and thereaftermicroscopically examining said sediment through the transparent side walls of said end portion.