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WBC diagnostic performance for appendicitis varies with age

July 22, 2016

Short Attention Span Summary

The diagnostic performance of WBC and ANC in pediatric patients with appendicitis varied based on age.  As age increased, overall diagnostic performance of WBC and ANC increased.  What this means is that clinical decision instruments for pediatric appendicitis, such as the Alvarado score or Pediatric Appendicitis Score would benefit from age-specific cutoffs for WBC and ANC.


Acad Emerg Med. 2016 Jun 2. doi: 10.1111/acem.13018. [Epub ahead of print]

The Influence of Age on the Diagnostic Performance of White Blood Cell Count and Absolute Neutrophil Count in Suspected Pediatric Appendicitis.

Bachur RG1, Dayan PS2, Dudley NC3, Bajaj L4, Stevenson MD5, Macias CG6, Mittal MK7, Bennett J8, Sinclair K9, Monuteaux MC1, Kharbanda AB10.

Author information:

1Division of Emergency Medicine, Children’s Hospital Boston and Harvard Medical School, Boston, MA.

2Department of Pediatrics, Columbia University College of Physicians and Surgeons, New York, NY.

3Department of Pediatrics, University of Utah School of Medicine, Salt Lake City, UT.

4Department of Pediatrics, University of Colorado School of Medicine, Denver, CO.

5Department of Pediatrics, University of Louisville, Louisville, KY.

6Department of Pediatrics, Baylor College of Medicine, Houston, TX.

7Department of Pediatrics, The Children’s Hospital of Philadelphia and Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA.

8Department of Pediatrics, Alfred I. DuPont Hospital for Children, Wilmington, DE.

9Division of Emergency Medicine, Children’s Mercy Hospitals and Clinics, Kansas City, MO.

10Department of Pediatric Emergency Medicine, Children’s Hospital and Clinics of Minnesota, Minneapolis, MN.



White blood cell (WBC) count and absolute neutrophil count (ANC) are a standard part of the evaluation of suspected appendicitis. Specific threshold values are utilized in clinical pathways, but the discriminatory value of WBC and ANC may vary by age. The objective of this study was to investigate whether the diagnostic value of WBC and ANC varies across age groups and whether diagnostic thresholds should be age-adjusted.


This is a multicenter prospective observational study of patients aged 3-18 years who were evaluated for appendicitis. Receiver operator characteristic curves were developed to assess overall discriminative power of WBC and ANC across 3 age groups: < 5 years, 5-11 years, 12-18 years of age. Diagnostic performance of WBC and ANC was then assessed at specific cut-points.


2,133 patients with a median age of 10.9 years (IQR, 8-13.9) were studied. 41% had appendicitis. The area under-the-curve (AUC) for WBC was 0.69 [95% CI, 0.61-0.77] for patients < 5 years of age, 0.76 [95% CI, 0.73-0.79] for 5-11 years of age, and 0.83 [95% CI, 0.81, 0.86] for 12-18 years of age. The AUC’s for ANC across age groups mirrored WBC performance. At a commonly-utilized WBC cut-point of 10,000/mm3 , the sensitivity decreased with increasing age: 95% (<5 years), 91% (5-11 years), and 89% (12-18 years) whereas specificity increased by age: 36% (<5 years), 49% (5-12 years), 64% (12-18 years).


WBC and ANC had better diagnostic performance with increasing age. Age-adjusted values of WBC or ANC should be considered in diagnostic strategies for suspected pediatric appendicitis. This article is protected by copyright. All rights reserved.

This article is protected by copyright. All rights reserved.

PMID: 27251399 [PubMed – as supplied by publisher]

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