BLOOD SAMPLER
The invention concerns a blood sampler for taking out small blood samples of the dimension a drop or so.
For many medical purposes it is necessary to take out small blood samples to determine different blood parameters such as glucose content, coagulation time etc. For this purpose the skin of the patient is pierced by a needle or stiletto to provide a small wound from which a single drop of blood is made to bleed out. The blood drop may e.g. be placed on a piece of indicator paper directly as it is often the case when the patient himself frequently makes the necessary determination of one of his blood parameters.
However, such measurement will often be made using electrochemically functioning apparatus having a sensor on which the blood drop must be placed. Such apparatus may be owned by the patient himself, but will usually be clinic equipment used for measuring of blood samples from many different patients. Unless the sensor on which the blood is to be placed is a disposable device which is disposed of each time a patient has placed his droplet of blood thereon the risk of dissimination of infection exists when a patient is directly placing his open wounded finger with the blood drop on a sensor contaminated by blood from a previous patient. This problem may be solved by using a disposable device for carrying the blood from the patient to the sensor. Such a device may be a small sponge into which the blood drop is absorbed and thereafter given off by squeezing the sponge at the sensor. This eliminates the risk as to the patient, but the handling of the free drop of blood on the patient's finger still presents a risk to the members of the clinic staff, especially when they have to help the patients by squeezing a pricked finger to make the blood flow or by wiping off excessive blood from the pricked finger.
The finger pricking may be performed by using a disposable lancet unit in a tool as described in Danish patent application No. 2316/90.
It is the object of the invention to provide a blood sampler by which the finger pricking and the absorption of a blood drop is obtained by using only one disposable article and without using any tool for operating the sampler, and by which the operator of the sampler is protected against coming into contact with the blood.
This is obtained by a sampler as described in claim 1. The sampler is placed with the spacing ring of the positioning part against the skin on the spot where a sample is to be taken. The sampler is pressed against this spot by pressing the bottom of the cover. The pressure on the cover is transferred to the sampling member, and when this pressure is sufficient to overcome the locking force of the pressure releasable lock, the sampling member is pushed downwards until it abuts the base of the positioning part, the needle of the sampling member passing through the opening in the positioning part and through the skin of the patient to a depth where small blood vessels are cut and blood therefrom will pass through the needle and accumulate as a drop at the other end of the needle under the cover.
During the sampling the sampling spot is well confined by the spacing ring which may be provided with an adhesive sealing bonding of the spacing ring to the sampling spot.
According to the invention the inner end of the needle may be provided with a collector with tongues which are bent outwards as petals to form a crown which may hold the blood drop preventing it from trickling down along the needle.
The cover may be made from a transparent material making it possible to inspect when sufficient blood has accumulated at the end of the needle.
Further the cover may be designed so that its opening fits narrowly over the outer side of the spacing ring. When placed fitting over the spacing ring, the cover may be used as a grip when the blood drop is to be transferred to another medium or the cover may serve as a base if the sample is to be stored for a time. At the same time the cover serves as a protection of the sharp needle end which projects from the bottom of the device when used.
In a preferred embodiment the positioning part may have the shape of a cup having the opening in its bottom and the spacing ring on the outer side of its bottom, the sampling member may have the shape of a cup fitting loosely into the positioning part with its open end in the same direction as the open end of this positioning part and may carry the needle in its bottom, and the cover may have the shape of a cup fitting loosely with its open end into the open end of the sampling member.
The pressure releasable lock may appropriately be provided by circumferential ribs on the inner side near the opening of the positioning part and 5 on the outer side near the bottom of the sampling part, respectively, a single rib on one part engaging the space between to neighbouring ribs on the other part.
The positioning part may further have ribs on its inner side near the bottom to lock the sampling member in its position with its bottom abutting the bottom of the positioning part when pressed. Thereby reuse of the device is 0 precluded.
According to the invention the needle may be a sprinkler-needle, which is a needle being pointed without being sharp and having in its side openings communicating with a central bore. Such needles seem to cause less pain and the wounds after the pricking will heal more rapidly as no cut is made in the tissue, s The invention will now be described in further details with reference to the drawing, in which
Figure 1 shows a sectional view of a blood sampler placed on a sampling spot ready for being pressed by a finger, Figure 2 shows the blood sampler of figure 1 with its sampling o member depressed with its needle projecting into the skin, and
Figure 3 the blood sampler of figure 2 made ready for giving of the sample to a measuring station.
The blood sampler in figure 1 comprises a positioning part having the shape 5 of a cup with a bottom 1 and side walls 2, the bottom 1 being provided with a central opening 9 being surrounded by a spacing ring 3 at the outer side of the cup.
A cup shaped sampling member having a bottom 4 and side walls 5 fits loosely into the positioning part with its open end in the same direction as the open end of the o positioning part. The sampling member is held in a position with its bottom placed near the open end of the positioning part, this position being obtained by an internal rib 6 near the opening of the positioning part engaging a circumferential groove 7 in the outer surface of the side wall 5 of the sampling member, which groove 7 here is provided as the space between two neighbouring ribs.
A hypodermic 8 needle is secured centrally through the bottom 4 of the sampling member and has a sharp pointed end directed towards the opening 9, and an end opening into the inner of the cup shaped sampling member. At this last end the needle is extended by a plastic tube, the free end of which by slots is divided into tongues 10, which are bend outwards as petals to form a crown.
The crown is covered by a cup shaped cover 11 fitting with its open end into the open end of the cup shaped sampling member and abutting with the edge of its opening against the inner side of the bottom 4 of the sampling member. The positioning part is placed with its space ring 3 pressed against the skin 12 of the person from whom the blood sample is to be taken. The sample is taken by pressing the bottom of the cover 11 by a finger 13. Thereby the positioning part will initially be pressed against the sampling spot whereby the skin is made ready for piercing, a pillow being formed from the skin inside the spacing ring. This has shown to lessen the sensation of pain. When the pressure has reached a sufficient magnitude the snap lock provided by the rib 6 and the groove 7 is released and the sampling member will pass down into the positioning member until its bottom 4 abuts the bottom 1 of the positioning part. Hereby the pointed end of the needle 8 is passed out through the opening 9 into to the skin 12 of the patient. The pointed end of the needle will cut some capillary blood vessels in the skin and blood will flow through the bore of the needle into the plastic tube and be collected in the crown as a drop 14 as shown in figure 2.
As further shown a circumferential rib 15 is provided on the inner side of the wall 2 near the bottom 1 of the positioning part. This rib 15 will engage the groove 7 when the sampling member is pressed down and this member will be locked in its pressed down position whereby reuse of the sampler is made impossible or at least unattractive.
The cover 11 may now be removed from its position covering the crown with the blood drop and may be fitted on the spacing ring 3. Thereby the needle which is now projecting through the bottom of the positioning part is covered to prevent anybody from being scratched by the pointed end. Further the cover acts as a grip by which the sampler may be handled to transfer the blood drop 14 to a sensor 16 or indicator.
The cover is preferably made from tranparent material to make it possible to inspect that blood is collected in the crown. If the blood does not of itself flow into the crown it may be helpful to sqeeze the skin around the sampling spot, which may be done without risk of coming into contact with the blood as the sampling spot is well confined by the spacing ring 3. This confinement may be made more effective by providing an adhesive on the edge of the spacing ring making it adhere to the skin around the sampling spot.