Abdominal Hernias Workup

Updated: Mar 16, 2023
  • Author: Assar A Rather, MBBS, MD, FACS; Chief Editor: John Geibel, MD, MSc, DSc, AGAF  more...
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Approach Considerations

Laboratory studies are not specific for hernia but may be useful for general medical evaluation. Imaging studies are not required in the normal workup of a hernia [7, 8] ; however, radiography, computed tomography (CT), or ultrasonography (US) may be considered in certain circumstances. Sigmoidoscopy is no longer recommended as a screening test.

Evaluation for potential reversal of provocative factors (eg, prostatism, chronic cough, severe constipation, rectal cancer, and ascites) is important.


Laboratory Studies

Laboratory studies that may be helpful include the following:

  • Stain or culture of nodal tissue - This can help diagnose atypical tuberculous adenitis
  • Complete blood count (CBC) - Results are nonspecific, but leukocytosis with left shift may occur with strangulation
  • Electrolyte, blood urea nitrogen (BUN), and creatinine levels - It is advisable to assess the hydration status of the patient with nausea and vomiting; these tests are rarely needed for patients with hernia except as part of a preoperative workup
  • Urinalysis - This can help narrow the differential diagnosis of genitourinary causes of groin pain in the setting of associated hernias
  • Lactate levels - Elevation may reflect hypoperfusion; a normal level does not necessarily rule out strangulation


Plain radiographs taken tangentially may show air in the intestine outside the abdomen, as may contrast studies of the bowel. Unfortunately, visualization of the perineum and pelvis is poor with these studies. Higher yields can be obtained with dynamic changes in position, intra-abdominal pressure, or both during the imaging studies. Better assessments of the perineum and pelvis are possible via external views of the intestine and their domain with herniography.

Careful instillation of water-soluble nonionic contrast through the abdominal wall helps to define most hidden hernias, such as interparietal, pelvic, obturator, sciatic, and other poorly palpable hernias (eg, small recurrent hernias). [28] However, unintentional luminal contrast injection may lead to infection.

If an incarcerated or strangulated hernia is suspected, the following imaging studies may be helpful:

  • Upright chest radiograph to exclude free air (extremely rare)
  • Flat and upright abdominal films to diagnose a small bowel obstruction (neither sensitive or specific) or to identify areas of bowel outside the abdominal cavity

Computed Tomography

CT of the abdomen and pelvis with oral and intravenous (IV) contrast can help detect many elusive hernias by demonstrating extracoelomic location of the bowel, bladder, or female internal reproductive organs. [29] CT may be indicated in the diagnosis of a spigelian or obturator hernia and in cases where the patient’s body habitus makes it difficult for the physician to perform a good physical examination.



US is helpful in narrowing the differential on both scrotal masses and masses below the inguinal ligament. It can also aid in the decision to drain or aspirate a nodal abscess. Like CT, US may be indicated when a spigelian or obturator hernia is suspected or when the patient’s body habitus hinders physical examination.

Infants with omphaloceles require prompt, thorough evaluations to detect associated anomalies. Initial studies should include bilateral renal US and echocardiography, as well as karyotyping and plain radiography of the sacrum.


Histologic Findings

Pathologic evaluation of pediatric hernia sacs offers little relevant clinical information. Tubular structures found during pathologic examination may indicate aberrant ductuli of Haller or duplications instead of segments of the vas deferens. Ductuli are 50-100 µm in size, much smaller than even the infant vas deferens; duplications can be proved only through reexploration.