A New Method for the Detection 
and Estimation of Sugar 
in the Urine. 
BY 
AETHUE E. ELLIOTT, C.M., M. D., 
INSTRUCTOR IN URINARY ANALYSIS 
AT THR FOST-GRADUATB MKDICAL SCHOOL, CHICAGO. 
REPRINTED PROM THE 
Weto York JHeUical Journal 
for July 27, 1895. Reprinted from, the New York Medical Journal 
for July 27, 1895. 
A NEW METHOD FOR 
TIIE DETECTION AND ESTIMATION OF 
SUGAR IN THE URINE. 
By ARTHUR R. ELLIOTT, C. M., M. D., 
INSTRUCTOR IN URINARY ANALYSIS 
AT THE POST-GRADUATE MEDICAL SCHOOL, CHICAGO. 
The tests most commonly used for the detection of 
sugar in the urine are the copper tests, and of these Feh- 
ling’s method has hitherto been the most popular with the 
profession. In common with the others of this class, this 
method depends for its reaction upon the power which 
grape sugar possesses of reducing cupric oxide to the state 
of cuprous oxide, with the formation of a yellowish-red 
precipitate soluble in ammonia. If sugar is present in the 
urine in any considerable amount, Fehling’s test leaves little 
to be desired as to reliability. When, however, but a small 
quantity is present, its method of application renders it 
liable to faulty reduction and misleading results. In deal- 
ing with small quantities of sugar in the urine it is any- 
thing but a perfect test. Normal urine contains substances 
which have a marked effect in reducing copper test solu- 
tions. The principal of these are uric acid and creatinin. 
I)r. George Johnson attributes to the former one quarter 
and to the latter three quarters of this property. They are 
Copyright, 1895, by D. Appleton and Company 2 
THE DETECTION AND ESTIMATION OF 
constant ingredients of the urine and constitute a fruitful 
source of error when but slight reduction takes place. 
Another occasional cause of faulty reduction of these 
tests is glycuronic acid. This substance is present in such 
small quantity in normal urine as to be considered practi- 
cally absent, but after taking such drugs as chloral hydrate, 
camphor, and chloroform it may appear in considerable 
amount. When such is the case it gives rise to a frank re- 
duction, indistinguishable in appearance from that pro- 
duced by grape sugar. 
The large quantity of urine used in the application of 
Fehling’s test renders it especially susceptible to these er- 
rors. In applying the test we are directed to add the urine to 
the boiling test solution until reduction takes place, or until 
we have added as much urine as we have test solution. The 
amount of the solution employed is usually one drachm. 
Such a quantity of normal urine, if it be at all concentrated, 
will almost invariably give rise to an appreciable reduction, 
much resembliDg that due to the presence of small amounts 
of sugar. It is with urines of high specific gravity that we 
exercise the greatest care in searching for sugar, and it is 
in these cases where discrimination is essential that Feh- 
ling’s method is most misleading. Normal urine is fre- 
quently concentrated, of high density, and increased acidity, 
and in such an event the amount of urine used with this 
test will contain sufficient creatinin and uric acid to produce 
a reaction which may, and frequently does, deceive the un- 
wary. If less urine is used the delicacy of the test is im- 
paired. In addition to this serious drawback, the instability 
of the test solution and its well known tendency under cer- 
tain circumstances to undergo spontaneous reduction are 
other objections to its use. Haines’s modification is a con- 
siderable improvement over Fehling’s in manner of applica- 
tion, but leaves much to be desired in point of delicacy. SUGAR IN THE URINE. 
3 
The ideal test for sugar will be one that is at once re- 
liable and sensitive, recognizing with certainty minute 
quantities of sugar in the urine, and one that requires the 
employment of never more than a few drops of urine in its 
application. Such a one the following method, devised and 
employed by myself, has thus far proved to be. With 
great reliability it combines extreme delicacy, and requires 
the employment of a minimum quantity of urine. 
The formulae for its preparation and the details of its 
application are as follows : 
Solution No. 1. 
Cupric sulphate (C. P.) gr. xxvij; 
Glycerin pure 3 iij; 
Distilled water 3 ijss ; 
Liquor potassae ad 3 iv. 
Dissolve the cupric sulphate in the glycerin and dis- 
tilled water. Gentle heat will facilitate the solution. 
When cold, add the liquor potassae and mix thoroughly. 
Solution No. 2 is a saturated solution of chemically 
pure tartaric acid in distilled water. 
The solutions are quite stable and will keep indefinitely. 
Into a test tube pour a drachm of the cupric-oxide 
solution and gently boil over a spirit flame. Then add 
two or three drops—not more—of the tartaric-acid solu- 
tion and boil again. Now add the suspected urine slowly, 
drop by drop, boiling and shaking the test solution between 
each drop until reduction takes place, or until eight drops 
of the urine have been added. If no change follows the 
addition of this amount of urine, sugar is not present. 
The end reaction is a yellowish or reddish, or sometimes 
greenish-gray, deposit of suboxide which is marked and 
unmistakable. Tf the solution be stood aside for a few 
moments the reaction deepens. 
Applied in this manner, the test will detect less 4 
THE DETECTION AND ESTIMATION OF 
than one part in a thousand of urine, or one tenth per 
cent. If sugar be present to any considerable extent, a 
single drop of urine will promptly develop the reaction. 
The addition of three drops gives a marked reduction 
when two grains to the ounce are present, and four drops 
will detect one grain to the ounce, or one in four hundred 
and eighty. More than eight drops of urine should never 
be used with this test, since that amount never fails to give 
a marked reaction when half a grain or more of sugar to 
the ounce is present, and smaller traces than this in the 
urine are of no interest to the practitioner. Greater deli- 
cacy may be obtained by the addition of a larger quantity 
of urine, but by so doing reliability is sacrificed for greater 
sensitiveness and the especial value of this method is de- 
stroyed. 
The end reaction developed by the smaller amounts of 
sugar is a grayish, muddy deposit, easily distinguishable, 
with disappearance of the blue color of the test solution. 
I have adapted this test so that it may be used for the 
quantitative estimation of sugar. The advantages which 
characterize it as a qualitative test render it especially ap- 
plicable for this purpose. Proceed as follows: Take a 
hundred and thirty-three minims of the cupric-oxide solu- 
tion in a narrow-necked glass tiask and add thereto six 
drops of the tartaric-acid solution and three drachms of 
liquor ammonise, U. S. P. Mix thoroughly, and add enough 
distilled water to raise the total volume of the solution to 
two ounces. The principle of this test is the same as that 
of Purdy’s test and Pavy’s ammoniated cupric test, which 
is that the cuprous oxide formed by the reducing power of 
the sugar is held in solution by the ammonia, the test so- 
lution remaining clear throughout, the end reaction being 
the complete disappearance of the blue color. 
This amount of the solution represents in sugar value SUGAR IN THE URINE. 
5 
a fourth of a grain of grape sugar—that is, it is reduced 
and decolorized by exactly a fourth of a grain of sugar. 
Its application is conducted in the same manner as Pavy’s 
and Purdy’s methods. The urine is added to the boiling 
test solution, drop by drop, until the color has entirely 
disappeared. The number of minims of urine necessary to 
produce this result is noted on the burette or minim pipette 
used, and four hundred and eighty, the number of minims 
in an ounce, is divided by the number of minims so re- 
quired, and the product divided by four, which gives the 
number of grains of sugar to the ounce. Instead of this 
process the urine, before testing, may be diluted with 
three volumes of distilled water, and four hundred and 
eighty, divided by the number of minims required to de- 
colorize the test, will give the number of grains to the 
ounce of urine. Knowing the total amount of urine for the 
twenty-four hours, it is a simple matter to estimate the total 
excretion of sugar. 
The delicacy of the test results in a singularly clear and 
transparent end reaction. This result is also partly due to 
the fact that the solution, being prepared freshly each time, 
is clearer and gives more positive results than other tests 
which, notwithstanding their alleged stability, deteriorate 
to some extent when kept for long periods of time. 
The fact that the same solutions are used for estima- 
tion as are employed for the detection of sugar consti- 
tutes an advantage, as it avoids multiplicity of reagents. The New York Medical Journal. 
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