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).
The litmus test is a quick method of determining whether a liquid or gaseous solution is acidic or basic (alkaline). The test can be performed using litmus paper or an aqueous solution containing litmus dye. Initially, litmus paper is either red or blue.