Taking the first few steps towards recovering from your opiate addiction is huge. No matter how you ended up with your opiate addiction, you can always take steps to get clean. However, an important first step is to understand what to expect during your first week or two of opiate withdrawal.
With anticoagulant = plasma (still has soluble fibrinogen). Without anticoagulant = serum ( fibrinogen has been converted into insoluble fibrin in clot and is spun down with cells). Source(s): Medical Scientist. liz down under Â· 9 years ago.
Sample/Specimen Considerations: Serum: Serum gel-barrier tube. Plasma: Green top tube, immediately place do not open tape over the top. Centrifuge and refrigerate as is. Place a piece of tape over the top of tube and write Do not open..