Diagnostic Testing in Low Pretest Probability Patients for Patient Reassurance

20 for repeat visit

Benefits in NNT

None were helped (decrease in illness concern, general anxiety, or symptom persistence)
1 in 20 were helped (avoiding a repeat visit)
0% were helped by a decrease in illness concern, general anxiety, or symptom persistence
4-6% were helped by fewer repeat visits

Harms in NNT

An unknown number were harmed (complications of testing like radiation, additional testing, false positive results, unnecessary interventions and additional cost)
An unknown number were harmed by complications of testing (radiation, additional testing, false positive results, unnecessary interventions and additional cost)
View As:

Efficacy Endpoints

Illness concern, general anxiety, symptom persistence, repeat visits

Harm Endpoints

Not addressed


Many physicians test patients at low risk of serious disease with the goal of providing reassurance, typically with the belief that this will lead to reductions in anxiety, symptoms, and patient concerns about their illness. This review reports on trials exploring the effects of testing on reassurance when the pretest probability of serious disease was low. In total, 14 randomized controlled trials of 3828 subjects met inclusion criteria.

No significant reductions were seen in anxiety, symptoms, or concern about illness (patients’ belief that their symptoms represented serious disease). A reduction in follow up visits was seen for symptomatic dyspepsia and back pain, with a number needed to treat of 16 and 26, respectively.

The studies in this review did not consistently examine harms of testing, which include complications of endoscopy and sedation, radiation exposure from imaging, and harms of false-positive results.

In the context studied, it appears that testing was not helpful in reassuring patients. Moreover, there are known morbidity and mortality risks associated with radiation exposure, intravenous contrast use and routine diagnostic procedures. Given the lack of significant patient-centered benefits, diagnostic testing for patient reassurance appears to increase health risks to the patient with little gain.


This article included a relatively large number of patients and selected only randomized-controlled trials. However, included studies were by necessity unblinded, many were older (1980s), and testing focused mostly on endoscopy for dyspepsia. Testing to assess other symptoms, and to ‘rule out’ other conditions, may have a different effect.

However, these results are important for physicians. It will be surprising for many to discover that laboratory testing (occasionally requested and desired by patients) is largely ineffective for the relief of anxieties and concerns felt by the patients in these trials, who were surveyed before and after their testing and results. It would appear that anticipatory guidance and patient-doctor dialogue may be more effective options than deferral to technological forms of assessing for underlying illness.

Importantly, this review focused on reassurance outcomes only in individuals with a low probability of serious disease, which the authors describe as somewhere between 0.5 and 3%. Patients were also studied in primary and secondary settings only (family medicine, internal medicine clinics), not in urgent care centers or emergency rooms or inpatient settings, where pretest probabilities may be higher or provider risk tolerance may be lower. Furthermore, use of diagnostic testing often depends upon local practice and perceptions of ‘acceptable miss rates’ for a given condition. Many included studies were performed in Europe, and are thus likely to be reflective of regional norms.

Finally, additional interventions and more active framing of negative results may offer more reassurance to patients than was seen in this review.1 2


Gary Green, MD


June 5, 2013