Color and transparency are determined from visual observation of the sample. Normal urine is straw yellow to amber in color. Abnormal colors include bright yellow, brown, black (gray), red, and green. These pigments may result from medications, dietary sources, or diseases.
limulus amebocyte lysate test. limulus amebocyte lysate test. LAL test. A test used to detect minute quantities of bacterial endotoxins and to test for pyrogens in various materials; it is also used to detect septicemia due to gram-negative bacteria. Limulus amebocyte lysate is formed from the lysed circulating amebocytes of the horseshoe crab (Limulus polyphemus).
Give a description of the tryptophanase test. We used a SIM medium (sulfur indole motility) tube. We stabbed it w/ a needle and streaked the surface. The next lab we looked for diffusion of growth from the stab line which indicates possible motility. A distinctive black pigment in the medium should be recorded as hydrogen sulfide (H2S). Then we added 1/4 inch Kovac's reagent and waited at least 1 min. but no longer than 5. A red color indicates it is indole positive.