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Efforts to reduce simultaneous ordering of ESR and CRP testing

C-reactive protein and erythrocyte sedimentation rate are commonly ordered together to assess inflammation, although the latter is a nonspecific inflammatory marker. Erythrocyte sedimentation rate (ESR) may remain elevated several days after an inciting inflammatory event and can fluctuate with other factors, including age, gender, and comorbidities. C-reactive protein (CRP) is more specific and sensitive for monitoring acute inflammation and can rise and fall at a rate similar to that of inflammatory response. Consequently, the American Society for Clinical Pathology (ASCP) developed a Choosing Wisely recommendation that discourages the routine use of ESR for patients who have undiagnosed conditions. Yet even with the recommendation, clinicians often co-order ESR and CRP. Of interest, studies have shown that false-negative ESR testing is common and that active inflammation is almost always present when ESR is normal and CRP is elevated. While interventions to reduce this pattern of co-ordering have been conducted in some health care settings, studies in resource-limited settings are lacking. The authors conducted a study in which they described a quality improvement project that used clinical decision-support tools to reduce unnecessary ESR testing across NYC Health + Hospitals, the largest safety net health care system in the United States. Their first intervention involved incorporating an informational nudge into the ESR order. This statement read, “H + H High Value Care Council does not recommend ordering both ESR and CRP when ordering inflammatory markers. Instead, use CRP alone.” The investigators added a detailed explanation of the potential harm of false-negative and false-positive results in the process instructions of the orders and a link to the ASCP Choosing Wisely recommendation. Their second intervention integrated a best practice advisory that triggered when the clinician ordered CRP and ESR simultaneously. This advisory read, “ESR and CRP are both being ordered. ESR is less sensitive and specific for acute inflammation. Click Accept to remove ESR order and continue ordering CRP.” The advisory defaulted to remove the ESR order. However, this advisory could be dismissed and the clinician could proceed with the order. The authors then analyzed ESR order rates per 1,000 patient days in the inpatient setting and per 1,000 patient encounters in the outpatient setting, as well as ESR/CRP co-ordering rates. The results showed that inpatient ESR orders decreased from 12.02 preintervention to 5.61 post­intervention per 1,000 patient days (-53.3 percent; P<.001). Outpatient ESR orders decreased from 6.09 preintervention to 4.07 post­intervention per 1,000 patient encounters (-33.2 percent; P<.001). Co-ordering rates showed a 50 percent relative reduction. Of interest, the CRP orders increased slightly through this intervention (eight percent inpatient without time trend and one percent outpatient with time trend). The authors noted that the smaller reduction in ESR use in the ambulatory setting may be attributable to patients likely being more stable than in an acute care setting, so ESR may be a better predictor of acute inflammation among this group. The authors concluded that using a nonintrusive normative nudge and a best practice advisory embedded in the EHR can help reduce inappropriate co-ordering of ESR and CRP. This is one of the first studies of a low-cost intervention for ESR and CRP co-ordering to change ordering practices in a cost-constrained large safety net health system. These efforts support the ASCP Choosing Wisely initiative of reducing unnecessary laboratory testing.

Cho HJ, Talledo J, Alaiev D, et al. Choosing Wisely and reducing the simultaneous ordering of erythrocyte sedimentation rate and C-reactive protein testing in a large safety net system. Am J Clin Pathol. 2023;160:585–592.

Correspondence: Dr. Hyung J. Cho at harryjcho@gmail.com