Response to Letter by Beetham and Lhatoo

Response:We are not surprised at the comments expressed by Drs Beetham and Lhatoo, outspoken advocates of a diagnostic test which is rarely used in North America. It is disingenuous, however, to claim that any diagnostic test is “owed” to patients before a demonstrated improvement in clinical outcomes. Although we acknowledge that of the 4 definitions of xanthochromia we studied, the UKNEQAS definition performed best in terms of sensitivity and specificity, our results did not support the use of any of the spectrophotometric definitions of xanthochromia. As discussed in the article, by using 4 discrete absorbances rather than a continuous scan to estimate the baseline, our method would err on the side of overestimating the specificity of the UKNEQAS definition and therefore represents a best case scenario. We also demonstrated that freezing had only minimal impact on our …