Reflective testing: how useful is the practice of adding on tests by laboratory clinicians?

To investigate the clinical value and practice of reflective testing, a new term to describe the practice of adding on tests when reporting or clinically authorising results.

A consultant medical biochemist collected over a calendar year (2001) copies of clinical biochemistry reports on samples to which he had added on either iron studies (iron, total iron binding capacity (TIBC), and percentage saturation), or vitamin D. Iron studies and vitamin D were added on when biochemical results, available clinical information, demographic data, and clinical experience-or combinations thereof-suggested the possibility of haemochromatosis or vitamin D deficiency, respectively. The number of reports that the consultant authorised was estimated for the same calendar year. The number and percentage of raised TIBC percentage saturation and low vitamin D results from the tests that were added on were collated.

Raised TIBC saturation values were found in 28 patients (18.7% of the iron studies added on), of whom 16 were subsequently genotyped, eight having a genotype consistent with haemochromatosis. Thirty one patients with vitamin D deficiency (23.1% of the vitamin D tests added on) were identified.

The addition of iron studies and vitamin D tests by a laboratory clinician, when reporting, resulted in the identification of patients with haemochromatosis and vitamin D deficiency. The practice of adding on tests should be called reflective testing, because it is discretionary and is based on the clinical judgement of a laboratory clinician in the interpretation of results.