Would labcorp be able to tell if a needle was tampered with when drawing blood?
If a nurse saw a needle that was unwrapped or tampered with they should throw it away. I've never heard of a lab re using needles to save money, when they could cut costs else where. I've never seen any one tamper with a needle when I go to have blood tests done. I'm sure other people wouldn't want to take a risk with contracting any thing from a needle. If they catch any one tampering with any thing they could be arrested or held by security. There are procedures to follow in any lab or doctors office, usually needles are wrapped individually and thrown away after it's been used. The last thing a lab needs is a law suit from a patient. I'm sure you have nothing to worry about. You might want to seek some help for your anxiety.
Would labcorp be able to tell if a vacutainer needle has been used or tampered with?
If they are the standard needles there is a a plastic bottom that contains the sharp end and a plastic cap that contains the end that screws onto the tube holder. When you open it you have to twist the top off the bottom as the two have been melted together. There is a very definite pop as that melted joint breaks apart. The top is immediately thrown away and the tech screws the needle inside the bottom part onto the tube holder. Then they remove the bottom part and throw it away and draw the blood. Once the blood is drawn they throw the needle away. The needle has to be thrown into a sharps container so it can not stick someone. For someone to tamper they would have to open up the needle, do whatever to it and then put the needle cap back on the bottom and remelt the two together. The next tech who uses the needle might spot something funny in how it breaks apart or might notice the funny melting of the two parts.