The recommended order of draw for blood specimens is essential to prevent cross-contamination of additives from one tube to another, which can affect test results. The correct sequence starts with blood culture, followed by light blue tubes for coagulation tests, then red tubes (which are usually used for serum tests without additives), followed by gold tubes (serum separator tubes), green tubes (heparin-containing tubes), lavender tubes (EDTA tubes for hematology), and finally gray tubes (which contain additives like sodium fluoride).
This order of draw is based on the types of additives in each tube. Blood cultures are taken first to prevent any contamination that could affect the results, particularly for detecting bacteria or other pathogens. The light blue tubes contain sodium citrate, an anticoagulant, which must be drawn before any tubes that might contain other additives to maintain the integrity of coagulation tests. The rest of the tubes are arranged based on the specificity of their additives and to minimize interference.
The other options do not follow the appropriate order and would therefore risk contamination or erroneous lab results due to mixing additives from different tubes. Each type of tube has a specific role, and following the established order is crucial for obtaining accurate laboratory results.