The Annals as a disseminator of guidelines and promoter of best practice

From time-to-time, the Annals has published or, critically appraised national guidelines. Where guidelines involve clinical biochemistry then their publication in the Annals enables them to be disseminated to relevant professionals in laboratories, not just in the UK, but also internationally. Such dissemination helps increase the uptake of any guideline and, hopefully, speeds up consequent improvements in practice. I will illustrate this point by considering the national guidelines for analysis of cerebrospinal fluid (CSF) for bilirubin in suspected subarachnoid haemorrhage (SAH). These guidelines first appeared in 2003 and were the culmination of much ‘behind the scenes’ work of many with an interest in this field. Until these guidelines were published, the analysis of CSF for bilirubin in relation to the investigation of SAH left much to be desired. The most important use of the test was/is to exclude SAH in patients who are negative for blood following computerised tomography (CT) scanning and thus to avoid subsequent cerebral angiography. In present times, due to pressure on acute beds, the test has developed greater importance in identifying these patients as they are unlikely to have suffered SAH and can therefore be safely discharged from acute locations. Much reliance has therefore been placed on this test by clinical staff. Historically, there has been much debate as to which is the best way of looking for bilirubin in CSF. Prior to the publication of the guidelines, the majority of laboratories used visual inspection of CSF, performed in microbiology laboratories as part of standard cellular and microbiological analysis. Visual evidence of a straw coloured fluid (hence xanthochromia) was used as evidence of altered blood in the CSF and publications at the time described findings based on visual examination, even though these may have not been well controlled. Such investigations, however, have one major flaw; namely they are subject to differences in human interpretation. In a desire to remove subjectivity from the investigation, in 1989, workers in the Netherlands recommended xanthochromia be ‘investigated by spectrophotometry’. This publication in turn led to an editorial appearing the same year in the Lancet. Although some laboratories took up the mantle of spectrophotometry following this editorial, much uncertainty remained as to the role of spectrophotometry and result interpretation. In response to this uncertainty, one of the first papers that appeared in the Annals in this area was published. It consisted of a Personal View, prepared under the auspices of the former Analytical Investigations Standing Committee of the Scientific Committee of the Association for Clinical Biochemistry. I believe this publication helped to kick-start the work that has appeared over the last 15 years, much of it in the Annals, that has turned this field from an art, to a more evidence-based science. Both the Dutch paper and the Lancet editorial, advocated the investigation of xanthochromia by spectrophotometry. Xanthochromia was defined as, ‘an absorbance, at 415 nm, of greater than 0.023 AU and/ or a peak in the absorbance curve in the 450–460 nm region’. In their Personal View, Beetham et al. found this definition of xanthochromia ‘unclear and ambiguous. ’ One aspect of their critique was that an increase in the concentration of CSF protein will result in an absorbance at 415 nm of more than 0.023 AU.