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Three Part Question

In [young children with suspected appendicitis] does [a single white cell count] aid [diagnosis]

Clinical Scenario

A 6 year old child presents to the Emergency Department - history and examination consistent with appendicitis. The duty surgeon requests a full blood count. You wonder if there is any recent evidence that this will aid the diagnosis.

Search Strategy

Medline 2002 – June week 2 2007 using the OVID interface
[{exp Appendicitis/ OR acute appendicitis.mp} AND {exp Haematological tests/ OR exp Leukocyte count/ OR leukocyte count$.mp OR neutrophil count$.mp OR white cell count$.mp OR inflammatory parameter$.mp} AND {exp Diagnosis/} AND {exp adolescence/ OR exp child/ OR exp child of impaired parents/ OR exp child, abandoned/ OR exp child, exceptional/ OR exp child, hospitalised/ OR exp child, institutionalised/ OR exp child, preschool/ OR exp child, unwanted/ OR exp disabled children/ OR exp homeless youth/ OR exp infant/ OR exp only child/ OR child$.mp Or exp Pediatrics/ OR pediatric$.mp OR paediatric$.mp}] LIMIT to human AND English

Search Outcome

41 papers were found of which 26 were irrelevant or of insufficient quality.
The remaining 15 papers are shown below:

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Yang HR et al 2006 Taiwan	897 patients (2-100) had appendicectomies. 82 % histologically confirmed appendicitis	Retrospective case review	Optimal WCC cut off 10.39x109/L	sens 85.8% spec 31.9%	No subset analysis for children No Powers calculation
			Mean WCC
			Nonappendicitis	12.1
			Inflamed appendix	14.2
			Perforated appendix	14.9

Comment(s)

This is a re-run of the BET 'White cell count and diagnosis appendicitis in children' - 2002. A large number of papers have been published on the subject since 2002. There are no consistently high values suggesting WCC is a reliable test in suspected appendicitis. The main trend throughout the papers is that sensitivity is greater than specificity (although neither significant). This implies that WCC is of some limited value in ruling out appendicitis if normal - but is not reliable to rule in appendicitis if high. There is repeated evidence that WCC increases with the stage of appendicitis - the greatest value of this test is in differentiating normal appendix or simple appendicitis from advance or perforated disease. A number of optimal cut off values of white cell counts were proposed. There were no consistently high values for sensitivity or specificity for any of the cut off points therefore none can be applied to practice. The proposal by Birkhahn RH et al. that WCC> 1300 = 'high likelihood' and < 9500 = 'low likelihood' is useful in principal and fits with the trend of increasing WCC with stage of appendicitis. However provides no information on the most frequent middle range results.

Clinical Bottom Line

A single WCC is not sufficient to aid diagnosis in suspected appendicitis - however in combination with clinical findings it may provide useful information particularly in distinguishing simple from advance appendicitis.

References

1. Yang HR Laboratory tests in patients with acute appendicitis ANZ Journal of Surgery 2006;76(1-2):71-4