Editing Viral load (section)

==Plasma specimens==
[[EDTA]] Plasma, from and EDTA blood sample is a good source of cell-free viral RNA for RNA-based viral load testing. Extraction of RNA from plasma requires specialized equipment, [[reagents]] and training, which might out of reach for medium to small laboratories. A large sample (> 1 mL of plasma) is needed requiring [[venipuncture]].
===Storage===
EDTA blood can be stored at room temperature for 30 hours, and  separated plasma for extended periods of time at -70&nbsp;°C without significant decreases in viral load.  

===Measuring===
Viral load is reported as copies of HIV RNA in a millilitre (mL) of blood. Changes in viral load are usually reported as a log change (in powers of 10). For example, a three log increase in viral load (3 log10) is an increase of 10<sup>3</sup> or 1,000 times the previously reported level, while a drop from 500,000 to 500 copies would be a three-log-drop (also 3 log10).{{cn|date=January 2021}}

===Other factors that affect viral load===
Different test methods often give different results for the same patient sample. To be comparable the same test method (target amplification, probe specific amplification, or signal amplification) should be used each time a patient specimen is run. Ideally patient testing should be conducted at the same medical laboratory, using the same viral load test and analyzer.