Heparin-Binding Protein for Bacterial Meningitis

This study came out highlighted by the last Emergency Medicine Journal Watch.

Now, I don’t want to steal Emergency Medical Abstracts thunder, since I’m sure they’re going to tear this article to shreds in a few months, but let me just comment on the conclusion of the Journal Watch reviewer that this is a “promising new biomarker that…might play the same role in bacterial meningitis that D-dimer does in venous thromboembolic disease” and that “an HBP level >20 ng/mL should prompt empirical therapy for bacterial meningitis” like this assay is something we should incorporate into our practice.

Part of the problem with this study is their methodology.  They used HBP to diagnose bacterial meningitis…in patients where they could diagnose bacterial meningitis.  Which means, these are all patients in which they already were able to make the diagnosis of bacterial meningitis without this magical new test.  So, immediately from that standpoint, it doesn’t add any value.

They also used two different samples, including, apparently, some they had on file from a decade ago – but their justification seems reasonable.

They compare the sensitivity and specificity of their test to the sensitivity and specificity of CSF polynuclear cells and CSF WBC count – and they’re statistically identical.  And, specifically, they are marginally better in absolute terms and likely in AUC vs. any of those tests individually, but when taken against the combined information given by all the CSF tests we already send off, there is likely no clinical difference.

Lastly, the most important words are on the first page: “Hansa Medical AB has filed a patent application on the use of HBP as a diagnostic tool in meningitis.  Dr. Linder, Dr. Christensson, Dr. Björck, and Dr. Åkesson are listed as inventors.”

My conclusion: this is an unnecessary test to add to your arsenal.  Read the article, make your own conclusion.

http://www.ncbi.nlm.nih.gov/pubmed/21200320