Final answer:
To collect serum, blood should be collected into a tube identified by a red cap. After blood collection, the blood clots and serum is separated from the clotted blood, which can then be harvested for analysis.
Step-by-step explanation:
To collect serum for medical analysis, blood is usually collected into a tube with a specific color-coded cap. In this case, blood should be collected into a tube identified by a red cap. The use of a red cap indicates that the tube may contain a clot activator and is intended for serum collection. During the hour after blood collection, the blood clots and the clot contracts, causing serum to be separated from the clotted blood. The serum can then be harvested for tests such as the VDRL test or to check for the presence of various components like antibodies, hormones, and other substances in the blood. In a healthcare setting, correct blood draw and color-coding of tubes are critical for accurate diagnosis and treatment.