Shifting dullness test evaluates the presence of ascites or intraperitoneal fluid
With the patient supine percuss the whole abdomen including the flanges. Note the distribution of dullness and resonance. Then place the patient on their side and wait for 30-60 seconds. Percuss the abdomen again this time systematically starting from the lower side (in contact with the couch) and move towards the upper side. If 500ml or more of ascetic fluid is present in the peritoneal cavity you should pick up consistently dull sounds from the lower side and resonance from the upper side. The level of dull sounds represents the amount of ascetic fluid present.
In positive shifting dullness test there will be consistently dull percussion sounds from the lower side and resonant sounds from the top side. The level of dullness represents the level of ascitic fluid present. In a negative shifting dullness tests there would be little difference noted in the percussion sounds compared with the supine position
Considerations: Factors affecting the shifting dullness test include an obese abdomen and excessive accumulation of faeces.