Example: If the urine had been diluted with 9 parts water, in other words, 10 times, the calculation would be 5 c.c. diluted urine = 0.5 c.c. actual urine.
| 0.01 | × 100 = 2 per cent. |
| 0.5 |
1500 × 0.02 (2 per cent.) = 30 grams of sugar in 24 hours.
Hill and Eckman perform the Benedict’s quantitative test as follows:[111]
Measure with a pipette 25 c.c. Benedict’s solution into a porcelain dish, add 5 or 10 grams approximately of solid sodic carbonate, heat to boiling, and while boiling, run in urine until a white precipitate forms, then add urine more slowly until the last trace of blue disappears. The urine should be diluted so that not less than 10 c.c. will be required to amount of sugar which 25 c.c. of reagent is capable of oxidizing.
Calculation: 5 divided by number of cubic centimeters of urine run in equals per cent. of sugar.
Fermentation Test for Quantity of Sugar in Urine.—If the urine is 70° F. (room) temperature when the specific gravity is taken at both the beginning and end of the test, it will assure accuracy.
To 100 c.c. of urine of known specific gravity, add one-fourth of fresh yeast cake thoroughly broken up. Mix thoroughly and set aside at a temperature between 85° and 95° F. for twenty-four hours, after which time test with Benedict’s or Fehling’s solutions. If reduction is obtained, it will be necessary to allow the fermentation to continue until it is complete. When no further reduction is obtained, the specific gravity is taken after the urine has reached a temperature of 76°. The difference in the specific gravity at the beginning and end of the test multiplied by 0.23 gives the percentage of sugar in the urine.
The following formulas represent the various solutions used in the above test: