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Three Part Question

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

Clinical Scenario

A 24 year old man presents to the Emergency Department with a history and examination consistent with 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 or white blood count$.mp)] LIMIT to human AND English.

Search Outcome

176 papers were found, of which 171 were irrelevant or of insufficient quality for inclusion. The remaining 5 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
Miskowiak J et al, 1982, Denmark	238 patients (>15) admitted with suspected acute appendicitis	Diagnostic test study, blinded	WCC>9 000. Histology	Sens 84%; Spec 66%; LR+ 1.26; LR- 0.95	No gold standard
Lau WY et al, 1989, Australia	1389 patients (1-87), with right lower abdominal pain, consistent with appendicitis 769 aged 15-65 Non-operative group followed up at 2 and 6 weeks	Diagnostic test study, blinded	WCC>10 000 (group 15-65). Histology	Sens 88%; Spec 76%; LR+ 3.7; LR- 0.29	No gold standard
Dueholm S et al, 1989, USA	204 patients (15-45) admitted with suspected acute appendicitis	Diagnostic test study, blinded	WCC>11 000	Sens 76%; Spec 74 %; LR+ 2.92; LR- 0.32	No gold standard
			WCC>9 000. Histology	Sens 83%; Spec 50%; LR+ 1.66; LR- 0.34
Amland PF et al, 1989, Sweden	110 patients (13-33) admitted with suspected acute appendicitis	Diagnostic test study, blinded	WCC>10 000. Histology	Sens 68%; Spec 69%; LR+ 2.19; LR- 0.69	No gold standard
Andersson RE et al, 1999, USA	502 patients (10-86) admitted with suspected acute appendicitis	Diagnostic test study	WCC>10 000. Histology	Sens 78%; Spec 68%; LR+ 2.44; LR- 0.33	No gold standard Unblinded Includes children

Comment(s)

All the reviewed studies have the weakness of no gold standard diagnostic test against which to compare the non-operative group. Only one study undertakes follow up of its non-operative group, with a single study formally recognising the fact that some abdominal pain, not requiring laparotomy, may have originated from the appendix. While all the studies seem to produce broad agreement as to the sensitivity and specificity of an isolated white cell count, they are not truly comparable due to the differing selection criteria of patients, age ranges and clinical management. In addition there is a wide prevalence of disease between the groups.

Clinical Bottom Line

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

References

1. Miskowiak J, Burcharth F. The white cell count in acute appendicitis. A prospective blind study. Dan Med Bull 1982;29(4):210-1.
2. 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.
3. Dueholm S, Bagi P, Bud M. Laboratory aid in the diagnosis of acute appendicitis. A blinded, prospective trial concerning diagnostic value of leukocyte count, neutrophil differential count, and C-reactive protein. Diseases of the Colon and Rectum 1989;32(10):855-9.
4. Amland PF, Skaane P, Ronningen H et al. Ultrasonography and parameters of inflammation in acute appendicitis. A comparison with clinical findings. Acta Chir Scand 1989;155(3):185-9.
5. Andersson RE, Hugander AP, Ghazi SH, et al. Diagnostic value of disease history, clinical presentation, and inflammatory parameters of appendicitis. World J Surg 1999;23(2):133-40.