Method and device for testing liquids

A method and device for testing a liquid such as urine for obtaining at least qualitative, but also quantitative, if desired, information in connection with a substance which may be present in the liquid. A reference body and at least one test body are dipped into and removed from the liquid which is to be tested, a suitable means being connected with the bodies to facilitate the dipping thereof into and the removal thereof from the liquid. The test body is capable of giving a color indication in connection with the substance while the reference body has characteristics substantially identical with those of the test cody except that the reference body is incapable of giving a color indication in connection with the substance. Thus, after removal of the bodies from the liquid the reflectivities thereof may be compared so as to give at least a qualitative, but also a quantitative, if desired, indication of the substance in connection with the liquid which is tested.

BACKGROUND OF THE INVENTION 
The present invention relates to the testing of liquid specimens such as 
urine and the like. 
In general, examination of a liquid such as urine is carried out with the 
use of color reaction test papers. At the present time test methods 
utilizing color reaction test papers are highly qualitative. Thus, in the 
strict sense, the known methods and devices will give an indication only 
as to whether or not the suspected constituent or substance is present or 
not present in the liquid such as urine. The primary reason for utilizing 
color reaction test paper so frequently, from among the various types of 
analyzing means which are available, is, in addition to its simplicity, 
the fact that the primary object of examining a liquid such as urine is to 
detect the presence or absence of abnormal substances such as glucose, 
protein, ect. which normally will not be encountered in the urine of a 
healthy individual. Clinically, the desired objective is almost entirely 
achieved simply by judging whether or not such substances are present or 
absent in the urin or other liquid which is tested. 
This reason, however, is in itself not sufficient for entirely supporting 
the present conditions of use of color reaction papers. Many urine samples 
which have been judged to give a positive or quasi-positive result after 
examination require further quantitative examination. Thus, these samples 
are further examined by quantitative analyzing means such as colorimetric 
analysis. For this reason it is a well known fact that clinical physicians 
are not satisfied only with the result of color reaction test paper 
examination. 
In addition, many specialists are doubtful of the ability of color reaction 
test paper to give a proper indication of the presence or absence of 
abnormal substances. Thus, it is well known that the capability of 
achieving a purely qualitative result is unreliable. 
In this connection the following example may be considered: 
It is well known that a pronounced coloring of the urine itself due to 
consumption of vitamin compounds by the individual or due to presence of 
bilirubin will cause errors in measurement. Due to the coloring of the 
urine itself from such causes, which are given only by way of example, as 
well as various other causes, it sometimes happens that the individual 
judging the test paper overlooks slight coloring of the color reaction 
test paper or believes that a detection has been made of a given substance 
by way of the color reaction test paper whereas actually the substance is 
not present and a false judgment has been made. Thus, with conventional 
color reaction test papers, the individual examining the test paper cannot 
always correctly judge the presence or absence of abnormal substances and 
there is a considerable possibility of erroneous judgment. Such erroneous 
judgment due to overlapping or confusion of the color of the urine itself 
and the color reaction represents a serious technical drawback which is 
inevitable when utilizing color reaction test paper. 
In order to achieve an accurate measurement it is necessary to use, instead 
of the unaided eye type of observation, spectral reflection measurement, 
with high-quality optical instruments being provided for this purpose. 
With methods of this type also, however, it is difficult to obtain 
entirely satisfactory results inasmuch as the spectral reflectivity of the 
color reaction test paper is observed under conditions where there is 
still an overlap or confusion between the color reaction due to reaction 
of the reagent in the test paper with the abnormal substance and due to 
coloring resulting from the colored constituents of the urine itself, as 
distinct from the substance the presence of which in the urine is to be 
tested. 
SUMMARY OF THE INVENTION 
It is accordingly a primary object of the present invention to provide a 
method and apparatus which will avoid these drawbacks. 
In particular, it is an object of the present invention to provide a method 
and apparatus capable of utilizing accurate color reaction measuring 
techniques with optical instruments for carrying out spectral reflectivity 
measurements while utilizing in addition certain advantageous techniques. 
Thus, it is an object of the present invention to provide by way of color 
reaction test paper not only an analysis with respect to detecting the 
presence or absence of an abnormal substance but also an analysis which 
will give a quantitative measurement value. 
Thus, it is an object of the present invention to provide a simple, 
convenient, and highly accurate and effective method and device for giving 
in connection with a substance in a liquid at least a qualitative 
indication and in addition a quantitative indication, if desired. 
According to the invention there are at least a pair of bodies one of which 
is a test body and the other of which is a reference body. These bodies 
have substantially identical characteristics with respect to liquid which 
is to be tested, except that the test body has the capability of giving a 
color indication in connection with a given substance whereas the 
reference body does not have this capability. A means is connected with 
these bodies to facilitate dipping thereof into and removal thereof from a 
liquid which is to be tested. By comparing the color difference, if any, 
between the bodies after they are removed from the liquid it is possible 
to achieve the desired information.

DESCRIPTION OF PREFERRED EMBODIMENTS 
Referring to FIG. 1, there is illustrated therein a structure which forms 
at least part of the device of the invention. However, as will be apparent 
from the description below, the invention is not restricted to what is 
shown in FIG. 1. 
The structure illustrated in FIG. 1 includes a test body 1 in the form of a 
color reaction test paper piece capable of reacting, for example, with 
glucose, protein, etc. when dipped into a urine specimen, the 
color-reaction test body 1 providing a coloring the intensity of which 
corresponds to the concentration of substances of the latter type when 
they are present in the tested liquid. This color reaction test paper 
piece 1 is generally produced by impregnating a white filter paper piece 
with a reagent which provides a given color as a result of a selected 
reaction with the glucose or other substance for which the test is made, 
the coloring having in the test paper piece a constant density. 
A reflectivity reference or compensation piece 2 is also made of a filter 
paper which may be the same as that used for the test body 1 and which is 
of the same configuration as the color reaction test paper piece 1. The 
color reaction test paper piece 1 and the reflectivity reference or 
compensation piece 2 are connected with a means to facilitate the dipping 
thereof into and the removal thereof from the liquid specimen. Thus FIG. 1 
shows an elongated strip 3 made of a suitable plastic, for example, and 
carrying the bodies 1 and 2 in the manner illustrated in FIG. 1, these 
bodies 1 and 2 being fastened to the strip 3 as by being adhered thereto 
with a material which is neutral with respect to the liquid and components 
thereof. Thus, the individual who uses the device simply holds the strip 3 
with his fingers and dips both the color reaction test paper body 1 and 
the reflectivity reference or compensation body 2 into the urine sample. 
The function of the reflectivity reference or compensation piece 2 is 
described below. 
In the schematic block diagram of FIG. 2 there is illustrated a spectral 
reflectivity measuring structure for measuring the spectral reflectivity 
of color reaction test papers, etc. Thus FIG. 2 shows a light source lamp 
4, a collimator lens 5, and a condensing lens 6. A filter 7 between 
components 5 and 6 permits passage only of light of a predetermined 
wavelength from the white light emitted from the light source lamp 4. The 
light whose wavelength has been selected by the filter 7 is condensed by 
the condensing lens 6, travels approximately vertically onto the surfaces 
of the color reaction test paper body 1 and the reflectivity reference or 
compensation body 2, and then is reflected in the direction 2 .pi.. A 
light detector 8 receives a part of the light reflected from the surface 
of the body 2 or the body 1 and transforms the received light into an 
electrical signal. While in the illustrated example there is shown a 
simplified structure receiving a part of the reflected light, it is 
preferable and possible to arrange an integration sphere type of optical 
system so as to cause the largest part of the 2 .pi.--direction reflected 
light to be received by the light detector 8. In FIG. 2 there is also 
shown a first-stage amplifier 9 receiving the output from the detector 8, 
and the output of the amplifier 9 is connected with a sensitivity 
adjusting circuit 10 having a sensitivity adjusting knob 11 and connected 
with an ammeter 12, so that by turning the knob 11 it is possible to 
adjust the position of the pointer of the ammeter 12, the latter having a 
reflectivity scale ranging from 0% to 100%. 
The above-described structure of FIGS. 1 and 2 is representative of a basic 
example of the present invention. This particular example operates as 
follows: 
The color reaction test body 1 reacts selectively with one of the abnormal 
substances in the urine sample and provides a coloring having an intensity 
corresponding to the concentration of the abnormal substance in the urine. 
The individual who is carrying out the analysis observes this coloring and 
can detect therefrom the presence or absence of the abnormal substance. 
However, it is difficult in this way to know the concentration of the 
abnormal substance in the sample. Moreover, it is all the more difficult 
and almost impossible to determine the degree of coloring with the 
unaided-eye observation in the event that the urine specimen itself is 
intensely colored. The reason why this latter situation obtains is now 
described with reference to the spectral reflectivity characteristic 
curves shown in FIG. 3. 
Referring to FIG. 3 the abscissa of the illustrated graph is plotted 
according to measured wavelength, while the ordinate is plotted according 
to relative reflectivity with the 100% reflection standard at each 
measured wavelength corresponding to that of the color reaction test paper 
piece 1 with pure water applied thereto. The curve A of FIG. 3 indicates 
the reflectivity characteristic of the color reaction test paper piece 1 
which has reacted with an abnormal substance of a certain concentration in 
the case where the urine sample is itself of no particular color. The 
curve B indicates the reflectivity characteristic of the color reaction 
test paper piece 1 with a urine sample applied thereto which contains no 
abnormal substance but which on the other hand is itself colored with a 
given intensity. While the characteristic of the curve B varies with the 
cause and degree of the coloring, in many cases the curve B will at least 
partly overlap the curve A. Therefore, with a urine sample which contains 
an abnormal substance which is to be detected and which furthermore is 
itself colored to a given degree for one reason or another, the 
reflectivity characteristic of the color reaction test paper piece 1 is 
obtained as a result of combining the curves A and B, with the addition of 
these curves being indicated by the curve C. Thus, the examiner or 
individual carrying out the observation sees the overall reflected light 
spectrum indicated by the curve C, so that it is not possible for such an 
individual to normalize the result simply by way of unaided-eye 
observation of the extent of coloring. 
The above problem is solved by way of the present invention in the 
following manner: 
The examiner grasps the strip 3 and dips both the test body 1 and the 
reference body 2 into the urine sample so that the urine sample is 
uniformly applied to both bodies. Then, after these bodies are removed 
from the sample measurement is made with the test body 1 and the reference 
body 2 applied to the spectral reflectivity measuring means, or in other 
words the optical means of FIG. 2. First the reflectivity reference or 
compensation piece 2 is placed at the predetermined measuring position in 
the optical means of FIG. 2, so that the reflected light is received by 
the light detector 8. Now the sensitivity adjusting knob 11 is suitably 
turned by the operator so that the ammeter 12 gives an indication of 100%. 
After this latter adjustment has been carried out, the color reaction test 
body 1 is situated at the measuring position. Now the ammeter 12 will 
indicate the reflectivity of the color reaction test paper piece 1. It is 
apparent that this latter reflectivity is of a value having a ratio with 
respect to the reflectivity of the reference body 2 corresponding to 100%, 
and accordingly this particular value is related only to the color 
reaction of the color reaction test paper piece 1. Thus, the reflectivity 
reference or compensation body 2 performs the same function as that of a 
sample blank used in colorimetric analysis. 
FIG. 4 illustrates the result of an experiment indicating that the 
above-mentioned operation can in practice be carried out. In this 
experiment a plurality of mock samples are utilized, these samples being 
made of urine containing corresponding abnormal substances but not being 
colored, with dye of various concentrations being added. A measuring 
wavelength is used which presents the most intense color reaction. The 
abscissa of the graph of FIG. 4 is plotted according to the relative 
reflectivity of the reflectivity reference body 2 with the mock samples 
applied thereto, with the standard value 100% of the reflectivity 
reference body 2 being the reflectivity thereof with pure water applied 
thereto. The ordinate of the graph of FIG. 4 is plotted according to the 
relative reflectivity of the color reaction test body 1 which is measured 
in the manner set forth above, but with respect to these mock samples. As 
is clearly apparent from FIG. 4, even if the reflectivity of the reference 
body 2 decreases by nearly 30% due to the coloring of the urine sample 
itself, the relative reflectivity of the color reaction test body 1 hardly 
changes. Therefore, according to the method of the present invention it is 
possible to carry out accurate measurement of abnormal substances in the 
tested liquid independently of the coloring of the urine samples 
themselves from causes other than the substance which is to be detected. 
The concentration of the abnormal substances can be obtained by previously 
obtaining the relation between the standard substance of known 
concentration and the relative reflectivity. There will be absolutely no 
erroneous judgment of the presence of the abnormal substance when there is 
no such abnormal substance in the urine. The above description relates to 
the operation and effect of one particular example of the present 
invention. Other modified examples of the present invention are possible, 
as described below: 
In the above example of the present invention, the reference body 2 is made 
of filter paper which is also the very same material used for the test 
body 1. However, the material used may be of other types such as cloth, 
paste-like solid material, etc. It is only required that the materials 
utilized for the reference body 2 have water-absorbing characteristics and 
dyeing characteristics similar to those of the color reaction test paper 
piece 1. The result of course is perfect if a material of entirely the 
same characteristics is used for the reference body 2 and the test body 1, 
with the latter differing only in connection with the reagent which gives 
the color reaction. Thus, in the above example of the present invention 
the reference body 2 is made of the very same material as the color 
reaction test body 1. Ideally it is preferable to use a material 
impregnated with various impregnating agents of the color reaction test 
body 1 and lacking only the color reaction for the suspected substance but 
otherwise having all of the other characteristics of the color reaction 
test body 1. 
It is easily possible to provide modified embodiments of the invention 
which will enable the operator to carry out examinations of a plurality of 
abnormal substances, so that the invention is not restricted in this 
respect. FIG. 5 shows one such modified example. Thus, referring to FIG. 
5, there are illustrated therein a plurality of color reaction test bodies 
1, 1', 1" which are in the form of the color reaction filter paper pieces 
and which respectively are provided with suitable reagents for giving 
predetermined color reactions when responding to the presence of 
substances such as, for example, glucose, protein, bilirubin, etc., with 
this embodiment also having the reference body 2 as described above. All 
of these bodies are carried by the common means 3. The device of FIG. 5 is 
operated in exactly the same way as that of FIG. 1, the only difference 
being that the device of FIG. 5 has the added advantage of being able to 
quickly carry out a plurality of different tests for a plurality of 
different substances in a single operation.