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Three Part Question

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

Clinical Scenario

A 6 year old individual presents to the Emergency Department with a history and examination consistent of appendicitis. On referral, the duty surgeon requests a full blood count. You wonder whether it will aid the diagnosis.

Search Strategy

Medline 1966-06/02 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

100 papers were found of which 96 were irrelevant or of insufficient quality. The remaining 4 papers are shown in the table.

Relevant Paper(s)

Author, date and country	Patient group	Study type (level of evidence)	Outcomes	Key results	Study Weaknesses
Doraiswamy NV, 1979, UK	375 children admitted with clinical diagnosis of acute appendicitis 225 found to have acute appendicitis, 50 with a normal appendix, and 100 in whom symptoms resolved spontaneously	Diagnostic test study	WCC>15 000 (0-10) or WCC>10 000 (10-15)	Sens 42%; Spec 97%; LR+ 12.5; LR- 0.60	Unclear if blinded No gold standard No follow up of non-operative cases
Miskowiak J and Burcharth F, 1982, Denmark	238 patients admitted with suspected acute appendicitis 74 were below 15 years	Diagnostic test study, blinded	WCC>15 000	Sens 19%; Spec 85%; LR+ 1.26; LR- 0.95	No gold standard
Peltola H et al, 1986, Sweden	162 children (1.9-15.6) admitted with suspected acute appendicitis	Diagnostic test study	WCC>15 000. Histology	Sens 60 %; Spec 84%; LR+ 3.75; LR- 0.48	Unclear if blinded No gold standard No follow up of non-operative cases
Lau WY et al, 1989, Australia	1389 patients (1-87), with right lower abdominal pain, consistent with appendicitis 177 children (1-15) Non-operative group followed up at 2 and 6 weeks	Diagnostic test study, blinded	WCC>15 000 (group 1-10). WCC>13 000 (group 10-15). Histology	Sens 60.5%; Spec 100%; LR+ INF; LR- 0.35	No gold standard Not analysed by age specific WCC Raw data not available for analysis by age group

Comment(s)

The majority of studies looked at absolute values of white cell counts in appendicitis and were of little use in evaluating its use as a diagnostic test. Although the paper by Lau et al is well constructed, it assesses two different ranges for the analysis, which may affect the results. Without data on the numbers within each group, their claim for 100% specificity, and infinite positive likelihood ratio must be interpreted with care.

Clinical Bottom Line

A single white cell count is neither sensitive nor specific in the diagnosis of appendicitis in children.

References

1. Doraiswamy NV. Leucocyte counts in the diagnosis and prognosis of acute appendicitis in children. Br J Surg 1979;66(11):782-784.
2. Miskowiak J, Burcharth F. The white cell count in acute appendicitis. A prospective blind study. Dan Med Bull 1982;29(4):210-1.
3. Peltola H, Ahlqvist J, Rapola J, et al. C-reactive protein compared with white blood rate and erythrocyte sedimentation count in the diagnosis of acute appendicitis in children. Acta Chirurgica Scandinavica 1986;152:55-58.
4. Lau WY, Ho YC, Chu KW, et al. Leucocyte count and neutrophil percentage in appendicectomy for suspected appendicitis. Aust N Z J Surg 1989;59(5):395-8.