Notably, this study was not conducted in a double-blind fashion and the induration was quantified by different readers. The authors suggested that the results from the pen technique must be interpreted with caution in that range. Our results comparing the two methods in a “double-blind” fashion indicate that the pen method is comparable to the
traditional palpation method when it is applied by the same experienced reader. We did not find any significant difference in any range of the measurement.
The results of our study are in agreement with those of Jordan et al, who tested tuberculous patients in a similar fashion. We found up to 18 percent false positive and false negative rate depending upon whether the pen or the palpation technique was used as the standard technique. Even though there was a highly statistically significant linear relationship between the measurements by the two methods (Fig 2), and there was not a statistically significant difference in the mean values of the studied categories (Tables 1 and 2), there could be some discrepancies in the individual patient. Our study does not indicate if a less experienced reader might achieve greater accuracy by the pen method in comparison to palpation, when his readings are compared with those of an experienced reader. Preliminary results in our department support this hypothesis. In conclusion, pen and palpation methods are comparable, if applied by the same experienced reader. Given the difficulties in using the palpation method by less experienced readers, the pen method might be a more appropriate method, but further studies are needed to verify this hypothesis. The results of this study showed that experienced readers can use either method with the same degree of accuracy.