Fig 1.
Method to photograph the tuberculin injection site.
A: Position the syringe proximal to TST injection site on forearm, at a distance equivalent to the width of a thumb. B: Position the smartphone distal to the injection site, at a distance equivalent to the length of the smartphone. C: Turn flash ON and hold the smartphone positioned so that the camera lens is at the top edge of the phone (and not against the arm), and pointed towards the tuberculin injection site. D: Tap the screen to focus on the TST injection site. Take at least 3 photos.
Fig 2.
Method to photograph TST induration.
A: Position the patient’s arm in-front of a black background. A pen or pencil should be held 2 cm above the site where the TST injection was given. B: Position the smartphone approximately one smartphone distance (lengthwise) from the patient’s forearm. C: Turn flash OFF and hold the smartphone positioned so that the camera lens is at the bottom edge of the phone (closer to arm) and pointed towards the induration. D: Tap the screen to focus on the induration site. Take at least 3 photos.
Fig 3.
Reading photos of TST injection site.
A: Using standard photo editing software (e.g. Microsoft Paint, or Preview), draw a digital line over the bleb at its widest point. B: Move the line to align with tick marks on syringe. C: Record the number of tick marks, and convert the measurement into millimeters.
Fig 4.
By bleb size (mm) reported by reviewers, for 78 measurements of blebs generated using the correct volume (0.1ml) of injected material and 18 which used the incorrect volume (0.05ml).
Table 1.
Agreement within and between each non-clinical reviewer and the reference standard for measurement and classification of TST blebs–judged as correct (7mm or more) or incorrect (less than 6mm).
Table 2.
Accuracy of mTST readings by five non-clinical (NC) reviewers, and one clinical-reviewer of 72 different photos of induration, compared to on-site measurement by an experienced TB nurse.
Readings categorized into 4 groups based on size of TST induration measured (using reference standard).
Table 3.
Accuracy of mTST readings by five non-clinical (NC) reviewers, and one clinical-reviewer of 72 different photos of induration, compared to on-site measurement by an experienced TB nurse.
Readings categorized into two size groups based on size of TST induration measured (using reference standard).
Table 4.
Within-reviewer agreement if induration present or absent on repeated evaluation of mTST photos of TST (performed 1 month apart) by five non-clinical (NC) reviewers and one clinical-reviewer.
Fig 5.
Proportion of reviewers who said that induration was present, by size of TST (mm) measured onsite by TB nurse.
Note: The size of the dots is proportionate to the number of readings.