Definition.—The presence in the urine of an abnormal quantity of indican. It occurs in small quantities in health.
Etiology.—"Indican is formed from indol,—C8H7N,—which is a product of the putrefaction of albuminous substances in the intestine. The indol is then absorbed from the intestines and enters the blood, where it becomes oxidized to indoxyl,—C8H7NO.—which immediately combines with potassium (and, to a slight extent, with sodium) sulphate to form indoxyl-potassium sulphate, in which form it is eliminated in the urine." (Ogden.)
All disorders, therefore, in which large quantities of albumin are decomposed, must be considered as causal factors in indicanuria. Such as carcinoma of the stomach, ileus, and all wasting diseases; cachexia, empyema, putrid bronchitis and gangrene of the lungs may be regarded as primary factors in giving rise to this condition.
Diagnosis.—This is made by using one of several tests, and demonstrating the presence of indican in the urine.
Tests for Indican.—Stokvis' modification of Jaffe's test is one frequently employed, and is as follows: place a few c. c. of urine in a test-tube; add an equal volume of concentrated hydrochloric acid, and two or three drops of a strong solution of sodium, or calcium hypochlorite. The mixture is shaken with one or two c. c. of chloroform. The indigo blue that follows reveals the presence of indican.
Take 15 c. c. of strong hydrochloric acid (C. P.) in a wineglass, add one or two drops of strong nitric acid (C. P.), stir; then add thirty drops of the urine to be tested, and stir immediately. An amethyst color soon makes its appearance, reaching its greatest intensity in from five to twenty minutes. If normal, a distinct but not intense amethyst color appears; if increased, the color is decided, and often very deep. (Ogden.)