What is a common preanalytical error that can affect test results during venipuncture?

A common preanalytical error that can affect test results during venipuncture is adjusting the order of draw. The order in which blood specimens are collected is crucial because different additives in the collection tubes can interfere with subsequent tests. For instance, if a serum tube is drawn before an EDTA tube, trace amounts of the serum can contaminate the EDTA sample, leading to falsely low results for certain tests, such as those requiring calcium testing. Maintaining the correct order of draw ensures that specimens remain uncontaminated and that analytical results are valid and reliable.

While improper labeling of specimens, using expired equipment, and inaccurate patient identification are also important factors that can influence test outcomes, they do not specifically pertain to the sequence of sample collection, which is vital for preventing cross-contamination of samples. Proper management of the order of draw is thus a crucial aspect of maintaining preanalytical integrity in lab testing.