Table 3: Techniques used to confirm NG position.

The techniqueComment

Insufflation test(i) Unreliable in small tubes or those with guide wire because of reduced airflow  
(ii) 20% false positive results [10, 11]

Gastric aspiration(i) Normal gastric aspirate is clear to slightly yellow  
(ii) Altered in gastrointestinal bleeding and bowel obstruction

Aspirated fluid pH and bilirubin(i) A pH less than 5 and bilirubin less than 5 mg/dL identified 98% of gastric sites  
(ii) A pH greater than 5 and bilirubin less than 5 mg/dL  identified 100% of the respiratory sites [12]

CapnometryReported high specificity and sensitivity rate [13, 14]

CapnographyCapnography was as accurate as colorimetric device for detecting CO2 during placement of NG tubes [15]

Magnetic guidance (i) Relatively new technique  
(ii) Rule out the presence of the NGT in stomach and lung