Diagnostic Accuracy of CRP & WCC in Abdomino-Pelvic Diseases of Non-Traumatic Acute Abdomen by Taking CT Findings as Gold Standard

Research Article

Austin J Surg. 2018; 5(5): 1142.

Diagnostic Accuracy of CRP & WCC in Abdomino-Pelvic Diseases of Non-Traumatic Acute Abdomen by Taking CT Findings as Gold Standard

Chauhan MN, Rehman S, Riaz M, Jonker L, Ali D, Zaman S and Canelo R*

Department of General & Hepatobiliary Surgery, Cumberland Infirmary Carlisle, UK

*Corresponding author: Ruben Canelo FRCS, Department of Hepatobiliary Surgery, Cumberland Infirmary Carlisle, Infirmary Road, Carlisle CA2 7HY, UK

Received: March 01, 2018; Accepted: March 21, 2018; Published: March 28, 2018


Acute abdomen is a common presentation to many emergency departments worldwide. It is important to differentiate self- limiting causes and serious surgical causes. Inflammatory markers such as WCC and CRP currently being used to determine the cause, assess severity and guide further investigation for acute abdomen. The aim of this study was to determine diagnostic accuracy of C - reactive protein and White Cell Count in abdomino-pelvic diseases of non-traumatic acute abdomen by taking CT scan findings as gold standard. We found that CRP levels of above 100 were highly sensitive (94%) and specific (92%) for an acute surgical abdomen. WCC was not as accurate at determining an acute surgical abdomen due to reasons such as neutropenic sepsis.


Abdominal pain accounts for 5-10% of presentation to the A&E department [1]. The “acute abdomen” is defined as “sudden severe abdominal pain of unknown origin” and is a very common cause for presentation to emergency department worldwide [1-5]. Diagnosis is dependent upon clinical assessment and investigations [3]. Clinical assessment involves a thorough history and clinical examination and is subject to variability based on clinical experience of examining physician [2]. Clinical examination has only been found to be accurate 47-76% of the time with only 50% of junior doctors and doctors working in community reaching a true diagnosis from the above alone [2]. Delay in diagnosis of acute abdomen affects instigation of treatment resulting in increased morbidity and mortality [5-7]. Serological markers of inflammation including C - reactive protein (CRP) and White Cell Count (WCC) are often used by clinicians as base line investigation to narrow down the differential diagnosis and guide further investigations including imaging.

The role of raise CRP and WCC have been extensively investigated with regards to their role in diagnosing acute appendicitis [3-5]. For example, studies have shown CRP sensitivities in acute appendicitis ranging from 40-94% and specificities ranging from 38- 87% [3-5]. However, little have been reported regarding the role of these two inflammatory markers in assessing patients presenting with acute abdomen in non-trauma abdomino-pelvic diseases. Sengupta et al. suggest that patients experiencing lower abdominal pain, with normal WCC and CRP, can be sent home [6]. CRP unlike WCC is an ‘add on’ blood marker in many trusts, not used routinely in A&E blood profiles.

Acute abdomen is a term frequently used to describe the acute abdominal pain in a subgroup of patients who are seriously ill and have abdominal tenderness and rigidity. Acute abdominal pain or disease may be caused by a myriad of diagnoses, including acute appendicitis, diverticulitis, cholecystitis and perforated bowel [10]. Computed Tomography (CT) of the abdomen and pelvis is considered the most appropriate examination for patient’s abdomino-pelvic diseases [11,12]. Non-enhanced CT, US, and conventional radiography are considered less appropriate initial imaging examinations for these patients [10]. But Ionizing radiation exposure at CT is associated with the risk of radiation induced cancer. This is a drawback of CT, especially as CT is increasingly being used in the diagnostic work-up of young patients [13].

Physicians in the emergency department often base their decisions for consultation of the surgeon for a laparotomy on clinical presentation combined with biochemical abnormalities. Examples of biochemical parameters include raised C-reactive protein (CRP) [14]. C-reactive protein (CRP) is a non-specific inflammatory marker that is used routinely in many hospitals as an aid in the diagnosis of patients with an acute abdomen [15]. One recent study conclude that biomarkers lactate and CRP in patients with acute abdominal pain should only be used in adjunct to the history and clinical findings, as they are not specific and can be misleading in establishing a diagnosis. In addition, relying on these biomarkers may contribute to more diagnostic examinations and/or unnecessary invasive interventions (for example laparotomy) [16].

Amore recent study reported the sensitivity of CRP (> 5 mg/l) 81.7% and the specificity 48.5% in patients with abdomino-pelvic diseases, they reported CRP at 48 h after hospital admission showed a good prognostic accuracy and can be used as an alternative to CT scan [17].

The rationale of this study is to determine diagnostic accuracy of C - reactive protein in abdomino-pelvic diseases of non-traumatic acute abdomen taking CT findings as gold standard. There are very limited studies available in the literature with the role of C-reactive in abdomino-pelvic diseases. This study will help us to provide a guide for an early diagnosis, so that patient may have an early diagnosis and successful treatment.

This study aimed to evaluate diagnostic accuracy, sensitivity and specificity of raised CRP and WCC both individually as well as collectively in patients presenting with acute abdomen of nontraumatic origin. Comparison was made with CT scan abdomen findings.


We retrospectively evaluated patients admitted with acute abdominal pain to the surgical department between January 2014 to June 2014.Data was entered on a structured proforma. Eligible patients were assessed and an initial diagnosis was made depending on a combination of history, clinical examination, laboratory tests and initial plain radiography. The final diagnosis was confirmed with CT scan. In total 396 patients were included with all basic demographics, such as name, age and sex being noted. CRP and WCC values within 24 hours of admission were recorded and its diagnostic value was then compared to CT scan results. CRP > 5mg/l and WCC >11 or <4 were set as being abnormal as per standard recommendation and literature reports.

The laboratory method used to measure CRP in serum was polyethylene glycol (PEG) enhanced immune-turbid metric assay. The CRP level within 24 hours of admission was recorded and its diagnostic value compared to the final diagnosis of all patients.

Data entry and analysis was performed using SPSS 20. We used chi-square test to compare continuous variable and Mann-Whitney U test for categorical variables.


A total of 396 patients fulfilled the inclusion criteria; 237 were females and 159 were males with a mean age of 59 years. 74% patient had positive CT scan results i.e. results in actual diagnosis rather than non-specific abdominal pain.

One hundred and fifty four cases had abnormal WCC (>11 or <4) and a positive CT scan abdomen findings. The specificity and sensitivity of WCC was therefore calculated as 72% and 52% respectively. The Pearson Chi-Square: p-value < 0.001 is highly significant; i.e. there is a trend that +ve CT is associated with abnormal WCC.

Table 1 highlights the specificity and sensitivity of CRP values only. Both the specificity and sensitivity increase significantly when CRP levels rose above 51. However, CRP levels between 6-50 were only 53% sensitive and 64% specific.