Device for determining a blood group

A device is formed with a closed chamber which contains a test serum, and which chamber permits the insertion of a blood sample to be tested. The blood sample and test serum react within the chamber, and the device includes optical elements, such as a magnifying lens, so as to view reaction test results. The test serum may be in a liquid or dry form.

The invention relates to a device for determining a blood group, in 
particular when performing a transfusion. 
It is prudent, before performing a blood transfusion, to verify that the 
blood which is about to be transfused does not have any incompatibilities 
with the blood of the recipient, with such incompatibilities arising, for 
example, from an error in labelling or an error in transcribing the blood 
group of the recipient. 
In particular, in some countries including France, regulations require that 
such verification should be performed at least with respect to groups 
A/B/0, since incompatibility in this respect gives rise to very serious 
consequences very soon after transfusion begins. 
Blood groups are usually determined by placing a drop of the blood to be 
indentified and a drop of test serum on a plate, with the appearance of 
the resulting mixture indicating the group. A variant of this method 
consists in using a test serum which has been crystallized onto a card 
medium. The test serum is then diluted using water at the moment of use 
and the blood to be tested is added thereto. 
These methods require awkward manipulations which also include risks of 
contamination for the manipulator since they take place in free air and 
thus under conditions of doubtful asepsis. 
The invention seeks to simplify the implementation of the verifications 
which are necessary before a blood transfusion. 
Another aim is to enable said implementation to take place under improved 
conditions of hygiene. 
Yet another aim is to make it easy to keep the result of the test fixed to 
the bag of blood which has been tested. 
The invention provides a device for determining a blood group, the device 
being characterized in that it comprises at least one closed chamber, 
means for inserting a sample of blood to be tested into said chamber in 
order to put it into contact with a test serum, and means for enabling the 
reaction of the test serum with the blood to be observed. 
Means may also be provided for inserting the test serum into the chamber. 
In a variant, the test serum may be present in the chamber in advance, 
either in the liquid state or in the dry state, e.g. in the form of 
crystals, or else impregnating a porous medium. 
In one embodiment of the invention, the chamber is closed in gas-tight 
manner and is placed under a vacuum before the blood is inserted therein, 
and the means for inserting the blood include a moving member suitable for 
putting the inside of the chamber into communication with a receptacle 
containing the blood to be identified, thereby enabling a sample of said 
blood to be sucked into the chamber. 
This ensures that the quantity of blood transferred into the chamber is 
determined by the degree of vacuum, i.e. by the residual pressure in the 
chamber at the moment when it is put into communication with the 
receptacle. 
According to a characteristic of the invention, the moving member is hollow 
needle which perforates a wall of the chamber. This needle may have points 
at both ends for respectively and successively perforating the wall of the 
receptacle and the wall of the chamber. 
In a particular embodiment of the invention, the device comprises a housing 
made of two parts each displaceable relative to the other and each 
displacable relative to the needle, with the chamber and the receptacle 
being contained in respective ones of said two parts and with the relative 
motion of said parts causing the wall of the receptacle and the wall of 
the chamber to be perforated successively by the points of the needle. 
Advantageously, the relative displacement of the two parts of the housing 
is a sliding displacement and the needle is guided in channels provided in 
the two parts and aligned in the direction of sliding. 
In a implementation of the invention, the perforatable wall of the chamber 
is defined by a plug which co-operates with one of the parts of the 
housing to constitute the sealed chamber. 
The plug may be pressed into a recess in the part in order to close it in 
sealed manner. 
When at least two chambers are provided, each intended for identifying a 
respective one of two blood samples by means of the same test serum, the 
two chambers may be juxtaposed along the length of a flexible hose 
received in a hollow in the second part and constituting the receptacle 
for the corresponding blood sample, with the relative displacement of the 
two parts taking place transversely to said direction. 
In the device comprising four chambers for identifying two different blood 
samples by means of two different test serums, it is advantageous to house 
two hoses in alignment with each other in an elongate hollow, with the 
hoses respectively containing the two blood samples to be identified and 
with the four chambers being aligned along the hose direction. 
Other characteristics and advantages of the invention appear from the 
detailed description given below and from the accompanying drawings, in 
which:

DETAILED DESCRPITION OF THE DRAWINGS 
The device shown in FIGS. 1 to 3 comprises two portions 8 and 9 which are 
connected by the hinge 17 enabling them to be closed against each other. 
When they are closed together in this way, the portions 8 and 9 define a 
housing 18 therebetween for an intermediate portion 13 of a flexible hose 
10, said intermediate portion lying between two zones 11 and 12 which are 
clamped between facing faces 19 and 20. Ribs 21 projecting from the face 
20 of the portion 9 co-operate with the face 19 of the portion 8 to close 
off the portion 13 in substantially leak-proof manner from the remainder 
of the hose 10. 
A needle 14 fixed to the protion 8 of the device projects into the housing 
18. This needle has a duct 16 running there-along right up to its end 
where it opens out into the housing 18, thereby connecting the housing 
with a closed chamber 1 provided in the portion 8. The chamber 1 is also 
connected to the housing 18 via another duct 5 which is closed by a 
hydrophobic membrane 5 which is permeable to the air. The chamber 1 
contains a porous medium 3 impregnated with a test serum in the dry state. 
The chamber 1 is separated from the outside of the device by a magnifying 
lens 6. 
Another chamber 2 is provided in the portion 8, likewise associated with a 
medium 3' impregnated with test serum, a duct 5' having a hydrophobic 
membrane 4', and a magnifying lens 6' similar to the items described under 
reference numerals 3 to 6 with reference to the chamber 1. Adjacent to the 
chamber 2 there is an element 7 which is capable of being perforated by a 
needle and which is accessible from the outside of the device. 
The device operates as follows: 
On being opened, the device is put into position shown in FIG. 3 enabling 
the flexible hose 10 connected to a supply of blood to be transfused and 
filled with said blood to be put into place between the portions 8 and 9 
running parallel to the hinge 17. Once the hose has been put into place, 
the two portions 8 and 9 of the device are closed over the hose as shown 
in FIGS. 1 and 2. Co-operation between the ribs 21 and the surfaces 19 
then isolates a volume of blood in the intermediate portion 13 of the 
hose. This intermediate portion presses against the surface 15 of the 
portion 9 delimiting the housing 18 and facing the needle 14, thereby 
ensuring that said needle is certain to perforate the wall of the 
intermediate portion 13 of the hose while the device is being closed. 
Under the effect of the pressure inside the portion 13 blood flows from 
said portion into the chamber 1, with said pressure being increased by the 
volume reduction due to the zones 11 and 12 of the hose 10 being pressed 
together over a certain length between the surfaces 19 and 20 of the 
portions 8 and 9. The empty space in the chamber 1 is filled with blood 
while the air originally contained therein escapes via the duct 5 and the 
membrane 4, with the membrane 4 preventing the blood from flowing out from 
the chamber. 
The blood reacts with the test serum 3 and the results may be observed 
through the magnifying lens 6. 
Further, the plug 7 is perforated by means of a needle 22 mounted on a 
syringe 23 and containing the recipient's blood thereby injecting said 
blood into the chamber 2. Air escapes from the chamber 2 and the reaction 
is observed in the manner described with reference to the chamber 1. 
Locking tabs 24 on the portion 8 co-operate with notches 25 on the portion 
9 and hold the device in its closed position. 
After observing that the same reaction has taken place in both chambers 1 
and 2, it is possible to proceed with the transfusion. If so desired, the 
device may be left in place on the hose 10, with the needle 14 remaining 
engaged in the hose wall. This makes it possible at any moment while 
transfusion is taking place to verify that the test has indeed been 
performed and to check the results thereof. 
The device described above identifies blood by means of a single test 
serum. In order to verify blood compatibility with respect to the groups 
A/B/0, it is necessary to use two test serums, anti-A and anti-B, so two 
devices can be used, one for each test serum. 
Another solution consists in using modified device including four chambers, 
i.e. a pair of chambers similar to the chamber 1 for the blood to be 
transfused and a pair of chambers similar to chamber 2 for the recipient's 
blood, with one chamber in each pair containing anti-A test serum and the 
other containing anti-B test serum. The relative positions of these four 
chambers depends on a design choice of the preson skilled in the art. For 
example, they may be placed in one or two lines behind a single face of 
the device or in pairs behind two adjacent faces thereof. Another design 
choice for the person skilled in the art concerns whether the two chambers 
for receiving the blood to be transfused are to be supplied via a single 
needle, via a branch in the duct thereof, or via two separate needles. 
The invention also covers a device including only one or two chambers for 
receiving blood to be transfused, and usable, in particular, for testing 
successive units of blood to be transfused to the same recipient whose own 
blood has already been tested while testing the first unit. 
The invention also covers a device comprising one, two, or four chambers or 
even more provided with an element such as 7 capable of being perforated 
by a needle and not including a built-in needle. Such a device having one 
or more chambers may be used for testing a single blood sample by means of 
one or more test serums, for expamle a blood sample taken from a person 
independently of any transfusion operation. With a suitable number of 
chambers, this makes it possible, in particular, to perform a complete 
blood group test of the kind performed in a laboratory. A device including 
an even number of chambers may be used for checking compatibility prior to 
transfusion when the supply of blood to be transfused is not connected to 
a flexible hose capable of being clamped and perforated, for example when 
the supply is in a glass bottle associated with a small test bottle. 
It is also possible to provide single chamber devices and to use an 
appropriate number of them as a function of the tests to be performed by 
putting them into place, where appropriate, individually along a flexible 
hose associated with a supply of blood. 
Whenever such a flexible hose is not available, the device may be 
simplified by omitting the hinge and the bearing surface. For use in 
conjunction with a flexible hose, the two hinged portions may be replaced 
by two separate portions provided with assembly means. e.g. by 
inter-fitting. 
Further, the needle 14 for perforating the hose may be replaced by a blade 
for cutting it. 
The various versions of the device in accordance with the invention may be 
stored in sterile packaging until they are used, thereby making it 
possible to perform blood tests under sterile conditions. 
The porous media 3 impregnated with test serum may be replaced by test 
serum in the liquid state, or in the crystal state without a supporting 
medium. In this case, the duct 16 must be narrow enough to prevent the 
crystals from escaping. If the serum is liquid, a non-return valve type of 
sealing device may be provided, e.g. in the form of a small ball. When the 
test serum is in the dry state, it may be advantageous to provide water in 
the chamber in order to dilute it in use, and this water may be contained 
in one or more frangible receptacles which are broken, e.g. by pressing 
against the lenses 6 made of flexible plastic material. 
It is also possible to omit inserting the test serum or the dilution water 
in the chambers in advance and then, when a test is to be performed, to 
inject them via elements such as 7 which need to be associated with each 
of the chambers, or to insert them by opening the chambers, e.g. by means 
of one or more covers provided for the purpose. 
The device shown in FIGS. 4 to 10 comprises two housing parts or portions 
31 and 32 which are slidable relative to each other. The upper portion 31 
has a groove 33 for receiving both a hose 34 coming from a bag of blood 
(not shown) and a test hose 35 for receiving a sample of blood from the 
recipient. 
The test hose 35 includes a plug 36 which can be perforated by a needle in 
order to insert the sample of the recipient's blood and a permeable plug 
37 for allowing air to escape. The upper portion also includes channels 38 
for guiding moving needles 39. 
The lower portion 32 includes a set of chambers 40 each of which is closed 
by means of plug 41 and each of which is provided with a channel 42 in 
which a corresponding moving blood-inserting needle 39 can slide. 
The hollow moving needles 39 are placed during manufacture in the channels 
42 and 38 of the lower and upper portions 32 and 31, and each end of each 
needle has a respective chamfer 39' or 39". 
In the embodiment shown, the device includes a set of chambers which are 
mutually separated from one another, and it preferably includes an even 
number of chambers so as to be able to test stored blood and the blood of 
the recipient simultaneously. Advantageously, the device includes four 
chambers with one pair of the donor's blood and one pair for the 
recipient's blood. 
The axis of the groove 33 in the upper portion 31 and the axes of the guide 
channels 38, 42 for needles 39 intersect at an angle lying in the range 
30.degree. to 60.degree.. This slope of the needle guide channels is to 
enable them to penetrate firstly into the test hoses 34 and 35 at a 
favorable angle that reduces the penetration force and also improves 
sealing at the location where penetration occurs. 
The device described above operates as follows: 
The chambers 40 are initially checked to verify that they are still under 
reduced pressure by examining the plugs 41 which should have a small 
central dip 40', with the pressure reduction in the chambers being 
obtained by any conventional means, for example by placing the device in a 
vacuum chamber at an appropriate moment during manufacture. 
The sample of recipient's blood is injected into the test hose 35 provided 
for the purpose. 
The test hose 34 from the blood bag is inserted into the groove 33 provided 
for the purpose and the upper portion 31 is pressed to a first ridge 43 to 
which it is locked by a catch 44. 
The application of a small amount of pressure causes the upper portion 31 
to slide in the lower portion 32 until it comes into abutment (FIG. 8) 
with the two parts being guided relative to each other by means of 
slideways 45 and 45'. 
The moving needles 9 begin by perforating the test hoses 34 and 35 
containing the blood to be tested and pass right through them until their 
chamfered tips 39' come into abutment against the bottom of the groove 33. 
The chamfer angle and its orientation are chosen so that the tips of the 
needles 39 are received in serrated portions 46 provided for this purpose 
in the upper portion 31 without establishing communication between the 
blood contained in the hose and the outside of the device (FIG. 9). 
Thereafter, under the effect of relative displacement between the two 
portions 31 and 32, the needles 39 pass through the thickness of the wall 
of the plugs 31 until they open out into the cavities 47 provided therein 
at reduced pressure. Under the effect of this reduced pressure, a 
calibrated volume of blood is sucked into each chamber 40 and is 
intimately mixed with serum previously placed therein (FIG. 10). 
The samples are inspected visually through the top walls of the chambers 
since the device is made of transparent material. 
During manufacture, test serum is inserted in the, or each, chamber 40 and 
preferably in the liquid state. Once the test serum has been inserted in a 
chamber, it is put under reduced pressure and closed by a plug 41. 
The chambers are shaped so that serum and blood mix in a uniform manner to 
provide a smooth thin film as can be seen from the FIG. 7 section through 
a chamber. This facilitates agglutination and makes it easier to perform 
visual comparison between chambers. 
The pressure reduction inside the chamber is adjusted so as to suck in a 
constant volume of blood and it is accurately matched to the volume of 
serum placed in the chamber so as to obtain an ideal mixture for 
agglutination and interpretation. 
By virtue of the catches 44 and the ridges 43, the device is provided with 
a system for locking the two portions together so that they cannot be 
moved apart after they have been used. Once the two portions 31 and 32 
have been locked together, the device remains fixed to the test hose 34 of 
the blood bag, thereby avoiding possible confusion. 
At no moment during the various stages are the test hoses 34 and 35 
subjected to pressure and there is therefore no danger of blood seeping 
out from the device. 
As with the device shown in FIGS. 1 to 3, the device shown in FIGS. 4 to 10 
may include various different numbers of chambers depending on its 
purpose. Similarly, each chamber may contain no test serum or may contain 
a a test serum which is liquid or dry.