Container Unit For Liquid Samples

Abstract

This invention relates to a disposable container unit for liquid samples and is particularly useful for the collection of blood specimens. It includes an elongated compressible bulb member having an integral nozzle attached thereto. An elongated storage volume having a closed and an open end and a small cross sectional area is also provided, the open end being in communication with the bulb member. Preferably but not necessarily the longitudinal axis of the storage volume, the bulb and the nozzle are coaxial. If the container unit is held vertically upward, liquid in the bulb will not flow freely into the storage volume because of its small cross sectional area. Similarly, if the storage volume contains liquid and is turned upside down, the liquid will not flow from it into the bulb.

Description

FIELD OF THE INVENTION

Our invention relates to container units for collecting, storing and treating liquid samples for analysis and is particularly useful for the collection of blood samples.

BACKGROUND OF THE INVENTION

Automatic analysis apparatus for performing a relatively large number of analyses on human blood samples is widely used in modern medicine as an aid in diagnosis and for screening large populations. In general, in the past it has been the practice to collect the blood for such analysis in a container which has been at least partially evacuated and to which a hollow hypodermic needle is attached. After the needle has been inserted in a vein of the subject, the passage between the hollow passage in the needle and the evacuated container is opened and the blood is sucked into the container. While this procedure has been widely used for the collection of blood samples in the past it has suffered from some deficiencies.

Among these is the fact that the container in which the blood is collected is not itself used to hold the blood sample for analysis. Rather, when analysis is to be done the blood is transferred to a receptacle used by the analysis machine and this blood is then analyzed. This transfer procedure presents opportunity for loss of sterility, spillage and possibly loss of patient identity because of clerical error.

Another problem with the prior collection and container systems was that relating to blood sample size. Conventional analysis machines require substantial amounts of blood for the generation of a complete profile of tests. Typically volumes of the order of 3 milliliters to 4 milliliters are required. By way of contrast, recently developed analysis machines may require only a few hundred microliters of blood for a complete blood profile. Such small volumes of blood may readily be obtained from children or elderly patients as well as healthy adults without trauma. Also these small volumes for analysis are obtainable from small animals without injury. Typically such small samples are obtained by cutting the finger, ear lobe or the like with a small lancet and collecting the blood by compressing a sterile bulb to which a nozzle is attached and then sucking the blood welling to the surface of the skin into the bulb. A novel disposable lancet for making precise incisions for the collection of small blood samples is disclosed in the co-pending application entitled "Snap Acting Surgical Lancet" filed Dec. 15, 1969, Ser. No. 884,861, which is assigned to the assignee of this application, and is in the name of W. Perry now U.S. Pat. No. 3,659,608.

Disposable sterile container units which can be used as the sample container in the analysis machine and are particularly useful in the collection of small blood samples have also been heretofore developed. Such containers are shown, for example in the following pending U.S. patent applications, assigned to the assignee of the present invention:

Inventors Title Ser. No. Filed C. Hurtig et al Clinical 884,924 Dec. 15, 1969 Sample Container A. Ferrari Dialyzing 65,540 Aug. 20, 1970 Liquid Collecting Container C. Hurtig Liquid 69,767 Sept. 4, 1970 Container Having Pressure- Protected Dialyzing Membrane

These applications are now issued as U.S. Pat. Nos. 3,640,267; 3,640,388; and 3,640,393, respectively.

While the containers described in the patent applications cited above are useful, they do anticipate use by a skilled technician to measure precise volumes. In practice it has been found that despite careful instruction, sometimes technicians do not collect the required volume of blood.

Further, the containers described contemplated the dilution of the blood sample and possibly its dialysis in the container itself. It has been found that in some cases it is more desirable to ingest a precise measured volume of the sample into the analysis machine and thereafter to precisely dilute it. Separation of the blood serum, which is used in analysis, from the red blood cells may conveniently be accomplished by centrifugation rather than dialysis, thus simplifying container construction.

Finally as has been mentioned above, it is a significant advantage if the collection container is disposable. The units described in the cited patent applications are relatively costly to manufacture as compared to the container of our invention.

From the foregoing it will be apparent that as automatic analysis machines have improved, a need has developed for a blood collecting and storage container, particularly for small blood samples, that would be relatively simple in use, economic in manufacture, adapted to centrifugation or other methods of serum separation, and useful not only to collect blood but also adaptable for use as a sample container in machine analysis.

It is therefore among the principal objects of our invention to provide a container unit which meets the foregoing requirements.

Another object of our invention is to provide a container unit of the type described in which the red blood cells and the blood serum may be separated in the field and then maintained in a separated condition during shipment to a central analysis location. A further object of our invention is to provide a container unit of the type described which may be manufactured by either blow molding or injection molding techniques conventionally used for the manufacture of large quantities of plastic products in an inexpensive manner.

A still further object of our invention is to provide a container of the type described which is convenient for the user to handle and which also may be used by relatively unskilled personnel.

Yet a further object of our invention is to provide a container unit of the type described which is generally useful for the collection, storage and treatment of liquid samples. These and other objects of our invention will be more apparent from the following detailed description and the accompanying drawings.

GENERAL DESCRIPTION OF THE INVENTION

Container units made in accordance with our invention include an elongated compressible bulb member at one end of which is formed a nozzle through which the liquid to be collected is ingested into the bulb. The bore through the nozzle is preferably but not necessarily coaxial with the longitudinal axis of the bulb. An elongated storage container is also attached to the bulb, preferably at the end of the bulb opposite to that of the nozzle. Preferably, but not necessarily, the longitudinal axis of the storage volume is coaxial with that of the bulb. The entire unit may be molded of a translucent or semi-transparent plastic such as low density polyethylene.

The cross sectional area of the storage volume i.e., its area measured in a plane normal to its longitudinal axis at the point of communication with the bulb, is sufficiently small so that the storage volume is not self-venting. This means that the liquid to be sampled may be aspirated into the bulb member and the unit then held vertically upward i.e., with the open end of the storage volume upward and its longitudinal axis vertical. Because the storage volume is not self-venting, no liquid flows into it. A marker on the portion of the bulb immediately adjacent the storage volume indicates that fraction of the volume of the bulb which is just sufficient to fill the storage volume. If sufficient liquid to fill the storage volume has not been ingested, more can be aspirated. If sufficient liquid is in the bulb, the technician merely "shakes down" the liquid into the storage volume in the same manner as one "shakes down" a clinical thermometer.

When the storage volume is filled, it may be inverted but the liquid therein will not flow outwardly because the volume is not vented. Any excess liquid in the bulb beyond that required to fill the bulb may be expressed from the nozzle.

The volume of the bulb is substantial as compared to the volume of the storage volume, usually being at least three times the storage volume.

DESCRIPTION OF FIGURES

A more complete description of container units made according to our invention is included in the following detailed description and the accompanied drawings in which:

FIG. 1 is a perspective view of the container unit of my invention;

FIG. 2 is a side plan view, partially in section, of a first embodiment of my invention;

FIG. 3 is a cross-section taken on the line 3--3 of FIG. 2;

FIG. 4 is a partial side plan view, partially broken away, showing the manner in which the liquid sample is contained in the bulb before being "shaken down" into the storage volume;

FIG. 5 is a view, similar to FIG. 4 showing the appearance of the storage volume after the sample has been "shaken down;"

FIG. 6 is a side plan view, partially broken away, showing the manner in which liquid is retained in the storage volume when in the inverted position;

FIG. 7 is a view similar to FIG. 5 showing the appearance of the storage volume after a blood sample collected therein has been separated into serum and red blood cells;

FIG. 8 is a view similar to FIG. 2 of an alternative embodiment of my invention specifically designed for molding by injection molding techniques; and

FIG. 9 is a sectional view taken along the lines 9--9 of FIG. 8.

SPECIFIC DESCRIPTION OF ILLUSTRATED EMBODIMENTS

As shown in FIGS. 1, 2 and 3 the container unit of our invention includes a relatively large bulb member 10 having a nozzle generally indicated at 12 integrally formed therewith. The storage volume, generally indicated at 14 is shown also preferably formed by a wall member which is integral with that which forms the bulb. A separable cap 16 is also provided for reasons to be explained below.

The embodiment of our invention illustrated in FIGS. 2 and 3 is particularly adapted and designed to be blow molded of low-density polyethylene or similar semi-transparent plastic material which is also at least somewhat resilient. The drawings of FIGS. 2 and 3 are scale drawings at twice the size of an actual device made in accordance with our invention.

The bulb member as shown in FIGS. 1 and 2 is an elongated cylinder with hemispherical ends, the length including the ends being about six times the internal diameter. The walls of the bulb are relatively thin so that they may readily be compressed by finger pressure to reduce the internal volume of the bulb. In an embodiment of a device fabricated of low density polyethylene the bulb walls were about 0.015 inch thick.

The nozzle 12 includes a cylindrical portion 12a, immediately adjacent the bulb and a tapering portion 12b. A bore of substantially uniform size extends through both portions of the nozzle into the bulb interior.

The cap 16 has an internal bore 16a whose surface engages the outer surface of the cylindrical portion 12a of the nozzle with a sliding frictional fit so that the cap may be readily removed, yet will remain in place when attached to the unit.

The storage volume chamber is formed by an elongated hollow cylindrical member attached to the bulb member at the end of the bulb opposite the nozzle end. As shown, the end of the storage volume secured to the bulb is open and the end farthest from the bulb is closed. It will be observed that the cross-section of the storage volume is quite small as compared to the diameter of the bulb. In the illustrated embodiment the internal diameter was approximately 0.131 inches, giving a cross-sectional area of 0.0135 square inches. The storage volume length was about 1.81 inches, the closed end being hemispherical in shape. This volume is sufficient to contain approximately 400 microliters of liquid. By way of contrast, in the illustrated embodiment, the total volume of the bulb is about 2,550 microliters. A "flag" or card 18 is integrally molded with the side walls which define the storage volume 14. This card is thicker than the side walls of the bulb and storage container. As illustrated it extends from just below the bottom of the storage volume part way up the bulb. In the embodiment illustrated, if the bulb chamber 10 is filled with an amount of liquid such that, when the container is held vertically upright, the upper surface of the liquid is in line with the top of the card and this liquid is then "shaken down," it will just fill the storage volume. Thus the volume of the portion of the bulb from its bottom to the top of the card is made just equal to the storage volume.

The card serves to stiffen the side walls of the storage volume and the bottom of the bulb so that they are comparatively rigid as compared to the upper portion of the bulb. It will also be observed that the card extends to the right of the container unit, as seen in FIGS. 2 and 3, a greater distance than to the left. This makes the unit relatively easy to handle and also permits the unit to be readily positioned in a tray or other unit provided with a suitable slot.

A slit 18a is provided in the card about mid-way between the two ends of the storage volume. The purpose of this slit will be hereinafter described.

When container units of my invention are to be used for blood sample collection, they are sterilized in any convenient manner and a solution of conventional anti-coagulant and anti-foaming materials in a volatile vehicle such as distilled water is placed in the bulb. The vehicle containing these materials is evaporated, leaving the walls of the bulb coated with crystals of anti-coagulant and anti-foaming material.

The manner in which the container unit of our invention may be used will now be described with particular reference to FIGS. 4 through 7. If blood is to be collected for example, the skin is incised as previously described and blood is allowed to well to the surface. The cap is then removed from a sterile container unit and the middle and upper bulb portion is squeezed between the finger and thumb to reduce the bulb volume. With the bulb in this condition, the nozzle is placed in the blood droplet and the pressure removed from the bulb. As it returns to normal volume it sucks in blood. The unit is then held vertically. If the sample collected is sufficient to fill the bottom of the bulb to the top of the card 18 (or such other marker as is provided) collection may cease. If it is not, additional blood is collected until the required volume has been obtained. It will be noted that in this process, none of the collected blood goes into the storage volume. When a sufficient sample of blood has been collected, the bottom portion of the container unit will appear as in FIG. 4.

Thereafter, the blood is shaken down into the storage volume by holding the container unit by the bulb portion and snapping the wrist in the same manner as one shakes down the mercury column in a clinical thermometer prior to use. The bottom portion of the container unit then appears as in FIG. 5.

If an excess beyond that required to fill the storage volume has been collected, after shaking down, the unit may be inverted and, as shown in FIG. 6, the excess blood will flow to the portion of the bulb immediately adjacent the nozzle, where it may be expressed to waste simply by squeezing the bulb. It will be noted however that the blood in the storage volume remains in place, even when inverted and does not flow into the bottom of the bulb 10.

A blood sample of known volume has thus been collected for analysis and the container may then be capped and sent to the analysis location. Alternatively, before sending the sample to the analysis location, the sample may be centrifuged to separate the serum from the red blood cells while in the container. After centrifugation the blood sample will appear as shown in FIG. 7 with the less dense serum portion in the upper portion of the storage volume as indicated by 19a and the denser red blood cells in the lower portion as indicated by 19b. To maintain the separation of serum and red blood cells between centrifugation and analysis, the storage container may be folded by folding the card 18 about the line 18b extending across the card from the slit 18a. Such folding collapses the side walls of the storage volume thus insuring a seal between the red blood cells and the serum. For shipment, the two portions of the folded card may be clipped together by a suitable clip and this may be removed at the analysis machine and the card unfolded.

For use as a sample container for analysis machines, the upper portion of the bulb may be simply cut off immediately above the top of the card 18 and the container unit placed in a suitable sample tray. The container unit of our invention has been designed particularly for use with the automatic analysis apparatus disclosed in the commonly assigned co-pending U.S. patent application of D. I. Kozowsky, A. Ferrari and C. R. Hurtig entitled "Constituents Measuring Chemical Analyzer Having Multiple Concurrently Operated Aliquot Processing Conveyors," said application having Ser. No. 105,805 and having been filed on the same date as the present application. Sampling apparatus particularly designed for use with the container units of our invention is disclosed in the commonly-assigned co-pending U.S. patent application of J. Bannister, M. Jordan and J. Peters entitled "Liquids Sampler With Probe Bathing Chamber," said application having Ser. No. 105,803 and having been filed on the same date as this application.

In FIGS. 8 and 9 we have illustrated another embodiment of a container unit of our invention. As mentioned above, this design is particularly designed for manufacture by injection molding. FIGS. 8 and 9 are also scale drawings of an actual unit and are twice actual size.

The unit of FIGS. 8 and 9 is made in two parts and these are fitted together to form the complete unit. The upper part generally indicated at 20 includes a nozzle portion 22, the upper portion of the bulb member 24, a cap 25 and an integral attaching strap 25a to permanently attach the cap 25 to the unit. The lower part, generally indicated at 26 includes the lower portion of the bulb member 28, the storage volume 30 and the "flag" or card 32.

It will be observed that the storage volume 30 and the lower portion of the bulb 28 are formed with walls of substantially greater thickness (about 0.030 inches) than the walls of the upper part of the bulb on part 20. The walls of the upper part of the bulb are about 0.015 inches thick in one embodiment and these are readily compressible when molded of low density polyethylene. It will also be observed that in the embodiment of FIGS. 8 and 9 the storage volume is not a right cylinder but tapers. This taper facilitates the withdrawal of the injection molded part from the mold. However the mean diameter is substantially equal to the mean diameter of the blow-molded unit shown in FIGS. 2 and 3.

A cylindrical collar 34 for receiving the lower portion of the part 20 is formed on the upper portion of the part 26. Several small hemispherical protruberances 36 are provided on the collar to facilitate the attachment of an identification device during processing if desired. The inner diameter of the collar 36 and the outer diameter of the lower portion of the bulb 24 forming a portion of part 20 are selected to form a close interference fit so that the two parts, when assembled as shown are sealed against leakage. The bulb member is provided with an integral shoulder 38 which engages the upper surface of the collar 36 to limit downward motion of the upper part when the two parts 20 and 26 are assembled.

It will be apparent that the container unit shown in FIGS. 8 and 9 will function in the same manner as that illustrated in FIGS. 2 and 3. It does have the advantage that the top need not be cut off when it is desired to use the lower portion of the bulb and the storage volume as a sample container. Rather the top portion 20 may be simply pulled out of engagement with the collar 34.

As has been described above, the storage volume of units made according to our invention is not self-venting as is a conventional water glass for example. As the diameter of the storage volume is increased, a size will be reached where this volume is self-venting and the liquid in the bulb will simply flow into the storage volume. We have found that in circular container units of our invention this largest diameter is of the order of 0.150 inches for water, blood etc. or the cross-sectional area is about 0.0177 square inches. If the diameter is larger than about this value, the storage volume may fill as the liquid is aspirated by the bulb and thus there will be no opportunity for determining when the desired volume has been obtained. Further there will be no assurance that the liquid, once in the storage volume will not flow out as the container unit is placed in various positions during shipment. If the storage volume is made smaller than about 0.040 inches in diameter, it is difficult to shake the liquid in the bulb into the storage volume.

While we have described the storage volume of our device as simply a relatively narrow closed container which is filled by "shaking down" the liquid in the bulb, it will of course be understood that the storage volume might include a vent opening at its lower end which is normally closed by a valve. When the liquid sample is contained in the bulb, this valve could be opened and the liquid would flow into the vented storage volume. Thereafter the valve could be closed to seal the vent and the liquid would not thereafter freely flow from the storage volume.

Additionally, while we have disclosed the concept of folding the storage volume to maintain the serum and red blood cells separated, it is apparent that the plastic tubing forming the storage volume might be heat sealed or a valve located about mid-way between the ends of the storage volume might be closed to achieve separation.

The storage volume of the container unit of this invention can be termed as being provided by a compartment. Further, it will now be apparent that this compartment provides a chamber that provides both a storage function and a measurement function.

It will also be apparent that, while we have described the use of the container unit of our invention in connection with the sampling, treatment and storage of blood samples, it will be equally useful in sampling other types of liquids such as urine or water in a sterile manner and providing a container from which they can be removed by the sampler of an analysis machine.

Thus, we have provided a low-cost container in which a known small volume of liquid may be collected, treated (as by centrifuging) and stored and which will retain the liquid once stored therein despite container unit orientation. With the upper portion of the unit removed, the lower portion may serve as a sample cup in connection with machine analysis of the sample. Thus the sample, once taken need never be removed from the sterile container in which it was collected. Because of the container units simple construction with resultant low cost, the entire unit may be disposed of once it has been used.

It will thus be apparent that this construction achieves the objects set forth above as well as those made apparent from the specific description.

Claims

Having described our invention what we claim is:

1. A container for the collection and storage of a liquid, said container comprising in combination

1. a bulb member having collapsible and resiliently restoring walls so as to be pumpable, and normally resiliently maintaining a first storage volume therein and normally having a minimal internal cross-section larger than a first area,

2. a nozzle affixed to said bulb member and having a liquid passage communicating through the wall of said bulb member with the interior thereof, and

3. a measurement and storage compartment having a second volume therein smaller than said first volume and affixed to said bulb member, the interior of said compartment communicating with the interior of said bulb member through an aperture of lesser cross-section than said first area and being fluid-tight except for said aperture, said aperture being sufficiently small to block the gravitational flow of liquid between said bulb member and said compartment.

2. The combination defined in claim 1 further comprising level-indicating means on said bulb member, said level-indicating means being so located on said bulb member that the portion of said first storage volume between said level-indicating means and said aperture, when said container is oriented with said aperture disposed directly below said level-indicating means, is substantially equal to said second volume.

3. The combination defined in claim 1 in which said container is made of low density polyethylene.

4. The combination defined in claim 1 in which said first volume is at least three times said second volume.

5. The combination defined in claim 4 in which said container unit is made of low density polyethylene.

6. The combination defined in claim 1 in which the cross-sectional area of said aperture is less than 0.0177 square inches.

7. The combination defined in claim 1 in which chemical materials to aid in the preservation of said specimen are included in said bulb member.

8. The combination defined in claim 1 in which said compartment is elongated and said second volume therein is of uniform cross-sectional area between the ends thereof with a value not greater than 0.0177 square inches.

9. Container apparatus for the collection of liquid material and for the storage thereof, said apparatus comprising

1. a collapsible and resiliently restoring pumpable aspirating bulb member normally having a first storage volume and having a nozzle for aspirating said liquid material thereinto, and

2. a measurement and storage compartment

a. having a known second storage volume less than said first volume,

b. having an open end feeding into said storage volume thereof from said bulb member for passing said liquid material from said bulb member into said compartment,

c. forming with said bulb member a normally-closed vessel open only at said nozzle, and

d. having the liquid-passing cross-section of said open end sufficiently small to preclude the free flow under at least gravitational force of liquid material between said compartment and said bulb member.