Related Experiment Video
Updated: Jun 8, 2026
Assessment of Child Anthropometry in a Large Epidemiologic Study
Published on: February 2, 2017
The tuberculin skin test: a comparison of ruler and calliper readings
H Geldenhuys1, S Verver, S Surtie
1South African Tuberculosis Vaccine Initiative, University of Cape Town, Cape Town, South Africa. hennie.geldenhuys@uct.ac.za
Background:
The Mantoux tuberculin skin test (TST) is widely used to diagnose latent infection with Mycobacterium tuberculosis. TST skin induration may be measured either by a transparent ruler or by a pair of callipers. We hypothesised that the type of instrument used may affect the reading.
Objective:
To determine whether variability in Mantoux TST measurement is affected by the type of reading instrument.
Method:
A TST (Mantoux method) was performed among healthy adolescents. The indurations were read with among ruler and calliper by two independent readers. Limits of agreement and Kappa (κ) scores at TST positivity cut-off points were calculated. A Bland-Altman graph was constructed.
Results:
The 95% limits of agreement between instruments ranged from -5 mm to 3 mm. The limits of agreement between readers ranged from -5 mm to 4 mm. κ scores between instruments were respectively 0.7 and 0.8 at 15 mm and 10 mm cut-offs.
Conclusion:
The variability between readers of TST indurations is not influenced by changing the reading instrument.
Related Concept Videos
01:26Pulmonary Tuberculosis IV
Several diagnostic approaches are used to detect TB. The conventional method is the Tuberculin Skin Test (TST), also known as the Mantoux test. However, this method has...
01:10Calibration Curves: Correlation Coefficient
01:14Assessing Body Temperature - Axilla
Step 1: Perform hand hygiene and put on clean gloves to maintain infection control and prevent cross-contamination.
Step 2: Prepare the patient by explaining the procedure to ensure understanding and cooperation. Ensure privacy, expose the axilla, and inform the patient that minimal movement is crucial for an accurate reading.
Step 3: Adjust the patient’s clothing to expose only the axilla. It minimizes...
01:14Temperature Measurement Sites
Oral: When assessing oral temperature, the thermometer tip should be placed under the tongue in the posterior sublingual pocket. It offers accurate readings and can be...
01:27Assessing Body Temperature - Rectal
Follow these steps for rectal temperature assessment:
Step 1: Perform hand hygiene and don clean gloves to prevent cross-infection.
Step 2: Position the patient in a side-lying position to better visualize the rectal...
01:23Assessment of blood pressure in brachial artery(two-step method)