Final answer:
Most specimens for therapeutic drug monitoring are collected with specific additives in tubes to prevent coagulation and maintain suitable plasma state for analysis. Quenching with solvents stabilizes analytes, and various in vitro techniques may be required for precise analysis.
Step-by-step explanation:
Most specimens for therapeutic drug monitoring are collected in tubes with specific stoppers to contain additives that preserve the integrity of the sample and will affect the blood analysis. Blood samples are often collected into tubes containing additives such as K2EDTA, lithium heparin, or dipotassium ethylenediaminetetra-acetic acid (K2EDTA). These tubes help to prevent coagulation and maintain the plasma in a suitable state for analysis. After collection, the blood is usually centrifuged to separate the plasma from the blood cells.
After centrifugation, quenching with solvents such as methanol can be performed immediately to stabilize certain analytes in the plasma, which is essential for accurate measurement during analysis. Urine samples may not require specific additives and could be analyzed directly without preparation. In certain cases, serum is collected by allowing blood to clot in a glass tube, followed by centrifugation to separate it from the clotted cells.
All these methods contribute to obtaining reliable data for therapeutic drug monitoring, which is crucial for the correct management of patient treatment. The choice of tube, the preparation of the sample, and the analytic techniques used must align with the requirement to get precise and accurate data. Furthermore, different in vitro techniques like equilibrium dialysis and ultrafiltration coupled with advanced analytical methods like LC-MS/MS might be required for analyzing very low levels of free drugs.