Glycosuria does not necessarily mean diabetes but if a patient under ordinary conditions of diet and in the absence of other special circumstances, passes urine which gives an unmistakable sugar reaction, the chances are at least nine out of ten that he has diabetes.

In applying the copper test, a muddy precipitate, which does not settle quickly and which does not present a distinct orange tint, often signifies salicyluric acid, due to salicylate medication or the use of preservatives, as in sweet cider.

Concentrated, "febrile" urine, of relatively high specific gravity, and a reddish tinge, especially if depositing urates, will almost invariably cause some reduction of copper solutions.

Almost any urine, if added to the copper solution in greater amount than that of the reagent, will, on boiling, produce a pale, yellowish green precipitate, which the over-anxious physician may interpret as indicating an appreciable amount of sugar.

While alimentary glycosuria may develop in a normal individual after the ingestion of large quantities of sugar (including syrup, candy, fruit, sweet cider etc.), it should not develop unless more than 100 grams of sugar have been taken at once and it often fails to appear after the ingestion of much larger amounts. (The writer, for example, has never excreted appreciable traces of sugar after various experiments with 200 - 500 grams of sugar.)

Alimentary glycosuria normally occurs when more than the following amounts of carbohydrates have been ingested at once, (von Norden.)

Starch, no limit on account of slow conversion; glucose, 200 grams; laevulose, 140 - 160 grams; canes ugar, 150 - 200 grams (saccharosuria may occur without glycosuria); milk sugar, 120 grams (corresponding to about 3 liters of milk); maltose, low limit, so that in many persons glycosuria almost always follows drinking beer; pentoses, low limit, so that nearly half is recovered from urine after administration of 30 - 50 grams.

The principal causes of non-diabetic glycosuria are:

Exogenic Toxins Causing Glycosuria

Curare, carbon monoxid, amyl nitrite, methyl-delphinin, morphine, chloral, hydrocyanic acid, sulphuric acid, mercury, alcohol, strychnine, salicylic acid (and salicylates), turpentine, uranium nitrite, benzol, acetone, phloridzin, phosphorus, cubebs and copaiba, diuretin, caffeine (the last two only when the diet is rich in sugar), chloralmid, ether and chloroform and narcotics generally.

Glycosuria Due To Disturbed Metabolism In General Diseases

Various infections, as cholera, intermittent fever, scarlet fever, cerebrospinal meningitis, as well as gout.

Central Nervous Glycosuria

Experimental puncture of the floor of the fourth ventricle, injury of the vermiform process of the cerebellum, high section of the spinal cord, and various traumatic and succussive injuries of the head, spine, and body generally. Idiopathic nervous diseases, such as major hysteria. Acute hydrocephalus, tuberculous meningitis.

In all suspicious reactions with copper solutions, the presence of sugar should be corroborated by the following test: Mix equal parts of urine and saturated solution of picric acid; add liquor potassae till a red color is produced: boil; a trace of sugar beyond the normal causes a very dark, almost opaque red.

There is no entirely satisfactory nor accurate quantitative test for urinary sugar. For approximate clinical work, either of the following may be used: 1. Add to a large test tubeful of urine, a piece of sugar-free compressed yeast; let stand 24 hours at a temperature of 70 - 100; each degree of specific gravity lost indicates one part in 500 or about 1 grain per ounce, of sugar.

2. Get at a reliable laboratory a standard, already mixed Fehling's solution, each 10 c.c. of which corresponds to a definite quantity of sugar, usually 5 centigrams. This will keep for several weeks. Dilute the urine from 5 times for specific gravities of 1020 - 1025, up to 10 times for specific gravities of 1035 and upward. Place 10 c.c. of the reagent, diluted with 50 c.c. of distilled water, (most oeconomically obtained from reliable water companies), in a conic flask of about 150 c.c. capacity which is set on wire gauze over a Bunsen burner. Drop the diluted urine from a burette into the flask, while the contents of the latter are boiling, until the reagent is decolorized and a deposit of copper oxid is formed. Knowing the amount of sugar to which the given amount of reagent corresponds, the dilution of the urine and its total quantity, the elimination of sugar is easily calculated. It is well to average two or three tests.

Polariscopes are expensive, their satisfactory use requires considerable and almost constant experience and many substances are likely to be present in urine which interfere with the result.

Modified medicine droppers are more troublesome and only slightly cheaper than burettes and the results obtained are very unreliable. Apparatus for measuring sugar by collecting carbon dioxid gas produced by yeast are more troublesome and expensive and no more accurate than the simple specific gravity test described.

A moderately severe case of diabetes on a mixed diet frequently eliminates 300 grams of sugar in a day. 100 grams is a moderate elimination for a mild case on a mixed diet. A "distinct trace" of sugar by the qualitative test means a measurable elimination of 5 - 10 grams in a liter or a liter and a half of urine. Less than this amount cannot be satisfactorily measured by clinical tests.

A loss in the urine of 50 - 100 grams of sugar a day, is not serious in itself, nor is the waste of this amount of nutriment a serious matter if the diet can be increased without notably increasing the elimination of sugar. While sugar in the urine may cause renal or lower urinary inflammation, nephritis coincident with diabetes is probably due to coordinate degenerative lesion.