Do you correct the synovial fluid white blood cell count for red blood cells, and if so, is there a rough approximation/equation you use?  

In a rheumatology practice, under most circumstances, there is no need to make a correction of the synovial fluid white blood cell count. The fluid is either translucent, transparent, or opaque and the count will help to establish the presence or absence of an infectious or inflammatory process and ...

Love the question as this does come up rather regularly in practice! I do adjust the synovial fluid white blood cell count for the presence of red blood cells that have made their way into the sample by the trauma of aspiration; this is different from a true hemorrhagic effusion (see below).It makes...