Response: Re: Signs and Symptoms That Rule Out Community-Acquired Pneumonia in Outpatient Adults: A Systematic Review and Meta-Analysis
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* Christian S. Marchello
* Mark H. Ebell

*To the Editor:* We thank Dr. Kazal for the comment on our publication “Signs and Symptoms That Rule out Community-Acquired Pneumonia in Outpatient Adults: A Systematic Review and Meta-Analysis.”1 Not only is lung ultrasonography a possible alternative to chest radiography (CXR) for the diagnosis of community-acquired pneumonia (CAP)2,3 but also they can be useful for the differential diagnosis of chest pain and dyspnea in the emergency department.4,5 We agree that point-of-care ultrasound (POCUS) should be explored in future studies on clinical decision rules for CAP, in addition to other point-of-care (POC) tests such as c-reactive protein.

However, POCUS is not yet ubiquitous nor has it replaced CXR as the current reference standard for diagnosing CAP. We express caution about the broad use of POCUS, as it suffers from subjective interpretation where interrater reliability varies6 and should be limited to clinicians with sufficient training and adequate patient volume.7 Most previous studies have been done in the emergency department or inpatient settings where there is a higher volume; whether primary care clinicians can duplicate that accuracy with lower volume requires further study. In addition, because pneumonia is relatively rare in primary care patients (about 3% to 4% of patients with lower respiratory tract symptoms), even a fairly accurate test can have a poor positive predictive value, leading to antibiotic overuse. We, therefore, advocate that future studies focus on the integration of simple heuristics, the overall clinical impression,8 validated clinical decision rules, and validated POC tests (eg, c-reactive protein)9 to identify patients at very low risk of CAP in the outpatient setting, as well as those who may benefit for further diagnostic testing, whether it be CXR or POCUS.

## Notes

*   To see this article online, please go to: [http://jabfm.org/content/32/5/000.full](http://jabfm.org/content/32/5/000.full).

## References

1.  1.Marchello CS, Ebell MH, Dale AP, Harvill ET, Shen Y, Whalen CC. Signs and symptoms that rule out community-acquired pneumonia in outpatient adults: a systematic review and meta-analysis. J Am Board Fam Med 2019;32:234–47.
    
    [Abstract/FREE Full Text](http://www.jabfm.org/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6NToiamFiZnAiO3M6NToicmVzaWQiO3M6ODoiMzIvMi8yMzQiO3M6NDoiYXRvbSI7czoyMjoiL2phYmZwLzMyLzUvNzUzLjMuYXRvbSI7fXM6ODoiZnJhZ21lbnQiO3M6MDoiIjt9) 

2.  2.Pereda MA, Chavez MA, Hooper-Miele CC, et al. Lung ultrasound for the diagnosis of pneumonia in children: a meta-analysis. Pediatrics 2015;135:714–22.
    
    [Abstract/FREE Full Text](http://www.jabfm.org/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6MTA6InBlZGlhdHJpY3MiO3M6NToicmVzaWQiO3M6OToiMTM1LzQvNzE0IjtzOjQ6ImF0b20iO3M6MjI6Ii9qYWJmcC8zMi81Lzc1My4zLmF0b20iO31zOjg6ImZyYWdtZW50IjtzOjA6IiI7fQ==) 

3.  3.Chavez MA, Shams N, Ellington LE, et al. Lung ultrasound for the diagnosis of pneumonia in adults: a systematic review and meta-analysis. Respir Res 2014;15:50.
    
    [CrossRef](http://www.jabfm.org/lookup/external-ref?access_num=10.1186/1465-9921-15-50&link_type=DOI) 
    
    [PubMed](http://www.jabfm.org/lookup/external-ref?access_num=24758612&link_type=MED&atom=%2Fjabfp%2F32%2F5%2F753.3.atom) 

4.  4.Buhumaid RE, St-Cyr Bourque J, Shokoohi H, Ma IWY, Longacre M, Liteplo AS. Integrating point-of-care ultrasound in the ED evaluation of patients presenting with chest pain and shortness of breath. Am J Emerg Med 2019;37:298–303.
    
    

5.  5.Zanobetti M, Scorpiniti M, Gigli C, et al. Point-of-care ultrasonography for evaluation of acute dyspnea in the ED. Chest 2017;151:1295–301.
    
    

6.  6.Gravel CA, Monuteaux MC, Levy JA, Miller AF, Vieira RL, Bachur RG. Interrater reliability of pediatric point-of-care lung ultrasound findings. Am J Emerg Med. In press.
    
    

7.  7.Ebell M. Point-of-care ultrasonography: an effective tool when used appropriately. Am Fam Physician 2019;99:143.
    
    

8.  8.Dale AP, Marchello CS, Ebell MH. Clinical gestalt to diagnose pneumonia, sinusitis, and pharyngitis: a meta-analysis. Br J Gen Pract. In press.
    
    

9.  9.van Vugt SF, Broekhuizen BD, Lammens C, et al. Use of serum C reactive protein and procalcitonin concentrations in addition to symptoms and signs to predict pneumonia in patients presenting to primary care with acute cough: diagnostic study. BMJ 2013;346:f2450.
    
    [Abstract/FREE Full Text](http://www.jabfm.org/lookup/ijlink/YTozOntzOjQ6InBhdGgiO3M6MTQ6Ii9sb29rdXAvaWpsaW5rIjtzOjU6InF1ZXJ5IjthOjQ6e3M6ODoibGlua1R5cGUiO3M6NDoiQUJTVCI7czoxMToiam91cm5hbENvZGUiO3M6MzoiYm1qIjtzOjU6InJlc2lkIjtzOjE3OiIzNDYvYXByMzBfMS9mMjQ1MCI7czo0OiJhdG9tIjtzOjIyOiIvamFiZnAvMzIvNS83NTMuMy5hdG9tIjt9czo4OiJmcmFnbWVudCI7czowOiIiO30=)