Which type of specimen is commonly collected for blood tests?

Venous blood is the standard specimen type collected for blood tests due to its reliability and consistency in providing accurate results. Venous blood is drawn from veins, typically in the arm, where it reflects the overall metabolic state of the body as it exists post-circulation before it enters the heart. This makes it ideal for a wide array of tests, from complete blood counts (CBC) to metabolic panels, as it provides a stable baseline for analysis.

While capillary blood may be collected for certain tests, such as glucose monitoring or for pediatric patients when venipuncture is not feasible, it is generally not as comprehensive or representative of the body’s overall condition as venous blood. Meanwhile, arterial blood is typically reserved for specialized tests, such as assessing blood gas levels, and is more invasive. Urine samples, while important for certain diagnostic tests, do not provide information specifically about blood components or systemic health in the way that venous blood does. Hence, venous blood remains the preferred specimen for a majority of standard blood tests.