OBERMAYERA TEST (F. Obermayer, the Austrian doctor, 1861 — 1925) — the method of high-quality chemical detection of an indican in urine based on transformation of a «animal» indican into indoxyl after hydrolysis of radio communication in its molecule by strong mineral acid and the subsequent oxidation of indoxyl ferric chloride to red indigotin (indigorubin) or blue indigotin (indigotin). Test is offered in 1890
to Hod of definition
Several milliliters of urine mix from 10% solution of a lead acetate (the tenth part of volume of the studied urine) for removal of the bilious pigments, salts and other substances preventing reaction and filter; 1 — 2 ml of a filtrate mix with an equal volume of a reactant of Obermayer (2 — 4 g of FeCl 3 in 1 l concentrated salt to - you) also add 0,5 — 1,0 ml of chloroform, carefully mix. If the layer of chloroform is painted in red or blue color, then O. of the item is positive. In reaction both the indigo ruby, and indigotin in various ratios therefore all shades of violet color of a layer of chloroform testify to positive O. of the item can be formed. At purification of urine it is impossible to increase quantity of a lead acetate since its surplus can neutralize salt to - that Obermayer's reactant. If urine contains salts of iodine, then chloroform is painted in rich red-violet color, to-ry disappears at addition of solution of sodium thiosulphate (200 g/l).
Urine of the healthy person contains insignificant quantity indican (see), a cut does not give positive O. to the item. At the strengthened decomposition of proteins in a human body (e.g., at malignant new growths, an empyema, bronchiectasias, abscess) and at intensive putrefactive processes in intestines (e.g., at strictures and invagination of a gut, tubercular peritonitis, a typhoid) there is eliminating of a side chain from a molecule tryptophane (see) and in intestines sharp increase in concentration is observed indole (see). If the formed indole is not removed with a stake, then it comes to blood and turns in a liver into an indican, to-ry is removed with urine; in all cases indicanurias (see) O. the item will be positive.
Bibliography: Todorov Y. Clinical laboratory trials in pediatrics, the lane with bolg., page 153, Sofia, 1968; About b e r-m e at e of F. tjber eine Modification der Jaffeschen Indicanprobe, Wien. klin. Wschr., S. 176, 1890.
B. K. Gorodetsky.