Background: This study assessed the agreement between infrared tympanic membrane (TM), axillary, corrected axillary (+0.5 degrees C), oral, and corrected oral (+0.3 degrees C) to rectal thermometry as reference standard in neutropenic adults. The sensitivity and specificity of the mentioned thermometries in detecting rectal fever (> or =38 degrees C) were also analysed.
Method: This is a comparative diagnostic test study. A total of 400 sets of blinded simultaneous temperature readings were measured from 21 haemato-oncology in-patients with neutropenia following chemotherapy. Three-hundred sets were then randomly sampled. Agreements were analysed using random two-way intraclass correlation (ICC). Sensitivity and specificity were analysed using contingency 2x2 table.
Findings: Both right and left TM thermometry have good correlation with rectal thermometry; 0.810 (95% CI, 0.748-0.855) and 0.770 (95% CI, 0.713-0.815) respectively. Axilla thermometry has weak agreement (ICC 0.486 (95% CI, 0.118-0.689)) with rectal thermometry. The sensitivity (sn) and specificity (sp) in detecting rectal fever (> or =38 degrees C) were: right TM (sn) 0.712 (95% CI, 0.586-0.814), (sp) 0.957 (95% CI, 0.920-0.978); oral (sn) 0.561 (95% CI, 0.433-0.681), (sp) 0.983 (95% CI, 0.954-0.995); and axilla (sn) 0.348 (95% CI, 0.238-0.477), (sp) 0.996 (95% CI, 0.973-0.999).
Interpretation: Single tympanic membrane thermometry is in good agreement with rectal thermometry. It is more sensitive than oral or axillary thermometry in detecting rectal fever.