US 2664752 A
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Description (OCR text may contain errors)
Jan. 5, 1954 s. G. souTHwlcK MULTIPLE PURPOSE HEMATOCRIT PIPETTE Filed Nov. 25, 1952 IN VEN TOR.
Patented Jan. 5., 1954 UNITED STATES PATENT OFFICE MULTIPLE PURPOSE HEMATOCRIT PIPETTE Samuel G. Southwick, Springfield, Ill.
Application November 25, 1952, Serial No. 322,539
2 Claims. (Cl. 'i3-4.25.4)
This invention relates to pipettes, and more particularly, has reference to a pipette of the hematocrit type, used for drawing an exact quantity of capillary blood for hematologic study.
Pipettes are used in laboratory analysis of blood, to determine the hematocrit of the blood, and to determine, in addition, the erythrocyte count, erythrocyte fragility, leucocyte count,
. hemoglobin concentration, blood sodium concentration, blood potassium concentration, and blood glucose determination.
The pipette which I have conceived is so designed as to permit the blood sample to be centrifuged While it is in the pipette, to determine its hematocrit before the blood is expelled and other determinations are carried out upon it. In this Way, the hematocrit and the other determinations mentioned above can be carried out, as mentioned, upon the same sample of capillary blood, and time can thus be saved in performing these determinations. In addition, the pipette which I have conceived is so designed as to obviate the necessity of a venepuncture, a venepuncture being required by most of the methods of hematocrit determination presently being followed.
ysummarized briefly, the pipette invention comprises a solid, one-piece, transparent body of molded glass or equivalent material, having at one end a pair of side by side longitudinal extensions of diierent lengths. A continuous bore is formed in the body, said bore being of a U shape, with the bight of the bore being disposed adjacent that end of the body remote from said extensions, said bight merging into elongated, parallel end portions extending longitudinally of the body within the extensions, and opening at the free ends of the extensions. The U-shaped bore formation, it may be noted, is so designed as to prevent the blood sample contained therewithin from being expelled during centrifugation of the pipette. Graduated scales are provided upon the body, extending longitudinally of the respective endportions, said scales being used during the making of a desired determination.
Other objects will appear from the following description, and claims appended thereto, and from the annexed drawing, in which like reference characters designate like parts throughout the several views, and wherein:
Figure 1 is an elevational View of a pipette formed in accordance with the present invention, as it appears when in use;
Figure 2 is an enlarged side elevational View of the pipette per se; and
Figure 3 is a cross sectional view, the scale being still further enlarged, taken substantially on line 2 3 of Figure 2.
The pipette constituting the present invention has been designated generally by the reference numeral I0, and is formed as a solid, molded body I2 of glass or other transparent material of non-corrosive characteristics selected for its adaptability for sterilization and cleaning.
The body I2 is relatively elongated, and is of approximately rectangular or oblong cross sectional configuration. One end surface I4 of the body is nat, as best shown in Figure 2, for a purpose to be made presently apparent. Said flat end surface I4 is rounded orf at its corners, and merges into elongated, straight side surfaces I6, I8 respectively, said side surfaces being transversely rounded in the preferred embodiment of the invention.
That end of the body I2 remote from the iiat surface I4 is integrally formed with straight, parallel, longitudinal extensions or tips 20, 22. The tips, as will be noted from the drawing, are of diiierent lengths, the tip or extension 2E] being approximately three times as long as the tip or extension 22. The free ends of the extensions are rounded oli, as best shown in Figure 2.
Formed in the body I2 is a continuous bore which, as shown in Figure 3, is preferably very small in diameter as compared to the diameter of either tip` of the body. The bore is of a U shape, having an elongated end portion 2li of straight formation from end to end, said end portion being disposed in closelyspaced, parallel relation to the side surface I6 of the body I2, and extending continuously from the free end of the longitudinal extension 20 to a location adjacent the end surface I 4. There the end portion 2A merges into a short bight portion 25 of the bore, extending transversely of the body I2 in relatively closely spaced, parallel relation to said end surface I4.
The bight portion 255 merges, in turn, into a straight end portion 28 of the bore, that is disposed in closely spaced parallelism with the side surface I 8 of the body. The end portion 28 of the bore extends within the short longitudinal extension 22, opening upon the free end of said short extension.
I provide, upon the body I2, a scale 30, said scale being calibrated in percent markings, from 0% to 100%. A second scale 32 is also provided, calibrated in millimeters or other suitable units. The scales 30, 32 overlie the end portions 24, 28 of the bore, each scale terminating close to the bight portion 20 at one end, and terminating at its other end in spaced relation to the longitudinal extensions 2e, E2.
ln use of a pipette formed in accordance with the present invention, the pipette would first be rinsed with a solution of heparin or some other suitable anti-coagulant. A hollow, rubber aspirator of the type used with hematologic pipettes is then attached over the short longitudinal extension or tip 22:, saidr aspirator being designated by the reference-numeral 35' and being shown connected to the extension 22, in Figure l.
Blood from a skin puncture (or, if desired, from:
a venepuncture) is then aspiratedthroughthe. elongated end portion 2li of the bore, to the zero end of the percent scale SG, that. isthat.end. of. the scale disposed adjacent the bight portion ii..
rlhe longitudinal extension' Zi'of the pipetteY i's then removed from the blood being aspiratedandi the blood column is sucked around the curve or bight portion. of the bore until the endsof. the blood` column in the bore coincide with. those: marks oi the scales Sil, 32. nearest the tip of.' the. pipette, that is, nearest that end of. the pipette provided with the longitudinal extensionslii, 22.
To determine the hematocrit of the collected. bloed, the aspirator is now remoyedand the pi-v pette is centrifuged, with the. longitudinal` extensions 2d, 22 of the pipette directed toward` the axis or the centrifuge, until the paoliing of the erythrocytesis achieved. The hematocrit. reading isthen taken from the. percent scale, at' the level or" the plasmaei-ythrocyteinterfase, that the top of the paokedlerythrocytecolumn.
The sedimentation rate of. the blood sample may be measured before the hematocrit determinationis made, by standing thepipette-.on itsiiat end surface ld', with the longitudinal. extensions- Zd, 22 extended upwardly as in Figure 2,., After' a predetermined period of. time (1. hour being usual) the amount of sedimentation. is read from thei scale t-Z. `Should itbe desiredl to. determine the sedimentation rate more rapidly, the4 pipette with its sample may bre-centrifuged. forV a. prede.- termined length of time equivalent. to. allowing the pipette tov remain stationary for an. hour. Thereafter, theY sedimentation rate,. that is,y the amount of sedimentation in millimeters or in other suitable units after the giventiine interval, is read from the scale 32. in a similar manner.
The icteric index of the blood sample may be D determined after centrifugation by matchingthey color oi the plasma layer in the pipette with the.. color of acueous solutions of potassium dichro.- mate, or with other suitablastandards. Itmay be noted that the plasma need not be removed from the pipette in making this determination.
After the performance of none, any, or all of the above tests the contents of the pipette'can be expelled and further determinations carried out on the blood sample.
The exact dimensions and proportions of the pipette can, of course, be varied, although it is preferred that the general proportions be substantially as shown in the drawing. It may be noted that a filling mark can beplaced upon one of the scales, as shown at 34, said filling mark being preferably located at the lower end of the scale 32. The lling mark, can however, be located at the lower end of the scale 30 if desired. When `the filling mark 34 is disposed at the lower end of the scale 32, the distance between the free end of the longitudinal extension 2t and the onehundred percent marking of the scale 30 must be equalfto the. length of the calibrated portion of theend portion Zdoi the bore.
It is also worthy of note that the free end of the longitudinal extension or tip Zi! may be shaped to,tastandardhypodermic needle, so as to permitftiie pipetteto be filled by means of a venepuncture desired.
It is believed apparent that the invention is not'necessarilyconfined to the specific use or uses thereof-. described above, since it may be utilized for any purpose to which it may be suited. Nor isthe invention to be necessarily limited to the specic construction illustrated and described, sincesuch constructionis only intended to beV illustrative, off the principles of operation and the means presently devised to carry out said princi,- plesit.being considered thatthe invention comprehends,V any minor, change in construction that may be` permitted within the scope of the appended claims.
What is claimed is:
1. 1n a pipette, a solid, transparent body formed with side by side longitudinal extensions of, different lengths at one of its ends,said body having a continuous bore substantially U-shaped with parallel endportions extending. within and openingl at thed free ends of'said extensionsthe bod'y having scale markings disposed longitudinally ofthe respective.endportions.
2.111 a pipette, a. solid,- transparent body formed with side. by ide longitudinal.extensions of different, lengths at, one. of its ends, said body havinga. continuous, bore substantially U-shaped with a.. bight. portion adjacent the other end of the body and with parallel end portions extending from the bight portion within said extensions andl opening at the free ends of the extensions, the body having scale markings disposed longi tudinally of, the respective end portions andterminating adjacent the bight and said extensions respectively.
SAMUEL G. SQUTHWICK.
References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 355,381 Chapman Jan. 4.-, 1887 FOREGN PATENTS Number Country Date 519,092 Great Britain Mar. l5, 1940 OTHER REFERENCES Ostwald Viscosity Pipette, shown in Fisher ScientiiicCo. Catalogue, p. 762, No. 13-695.