An erythrocyte sedimentation rate (ESR) and a C-reactive protein (CRP) are often ordered together, but many times provide similar information. An ESR is a measure of acute phase proteins in the plasma. A CRP is a proinflammatory acute phase reactant “which responds to infection and trauma by activating the complement/phagocytosis components of the immune system.”
Inevitably with the two tests, there is a higher sensitivity; for example, with osteomyelitis, one study found the paired testing had a 98% sensitivity compared with a 95% sensitivity for CRP alone (not statistically significant). However, the authors note that “concordant or discordant results also have been found to lack clinical utility.” As a consequence, the authors decided to investigate the costs of pairing these tests. At their 739 tertiary care hospital, the additional cost resulted in charges between $250,000-400,000 more than ordering a single test. They extrapolate the cost to $300 million nationally.
Take-home message: If you were spending your own money &/or trying to be a good steward of someone else’s, could you justify the expense of routinely obtaining both an ESR and a CRP?
Related blog post:
gutsandgrowth 
Already addressed in pediatric UC: http://www.ncbi.nlm.nih.gov/pubmed/21939916
But, there’s still 1/3 in which one or both don’t reflect disease activity. I still order both.
Routinely ordering both CRP and ESR should be looked at more carefully. I suspect that if one looks at each patient on an individual basis that there will be many circumstances when ordering both on every blood draw would not be needed (as indicated by your reference).