Clinical virology has come of age since reliable and rapid diagnostic tests have become available for most viral infections of humans, mainly due to advances in molecular approaches. In addition, the increasing number and use of general and specific antiviral agents have driven the development of drug susceptibility assays and the definition of particular mutations in viral clinical isolates conveying resistance to particular antivirals. Last but not least, many human infections and diseases which have emerged or re-emerged over the past 20-25 years have viruses as their cause, often infecting the human host after zoonotic transmission.

The Clinical Virology Manual is a collection of test procedures aimed at providing a comprehensive, reliable and rapid diagnostic service. The 4th edition has been considerably updated in describing modern diagnostic procedures, in particular molecular techniques. The first chapters provide very useful advice for setting up a diagnostic virus laboratory. Quality assurance (QA) and quality control (QC) are as important as proficiency testing (PT), and in many countries laboratories face serious sanctions if several rounds of PT have had an unsatisfactory outcome. High quality equipment and reagents are as important as are appropriate and continuous training and assessment of staff. The suitability of particular clinical specimens is crucial for obtaining a meaningful diagnostic result, and this topic is given detailed attention. The important issue of evaluation criteria of new diagnostic tests has not been addressed.

The general part of description of laboratory procedures contains chapters on virus isolation, electron microscopy, enzyme-linked immunoassays, neutralization tests, haemadsorption, haemagglutination and haemagglutination inhibition, testing for virus-specific IgM antibodies and their interpretation. Viral susceptibility tests and Western blotting procedures are mentioned, regrettably without concrete examples. More room is given to the description of molecular procedures, i.e. nucleic acid detection and amplification techniques, including test variants allowing quantitation of viral nucleic acid in body fluids ('viral load'). Regrettably, good illustrations of test principles, results and their interpretation are scarce. A list of the many abbreviations used in this book would have been very helpful.

The chapters on specific viruses and the diseases they cause are of varying quality. Rather dry chapters are interspersed by others where molecular diagnostic approaches are supported by good descriptions of the underlying molecular biology of viruses. The references are frequently, but not always up-to-date. On the other hand, recently discovered viruses infecting humans (e.g. metapneumovirus, bocavirus, new polyomaviruses, TT virus, etc.) receive attention. To this reviewer, the scarcity of data on drug resistance mutations in the genomes of major human pathogens (HIV, hepatitis viruses, influenzaviruses, viruses of the Herpesviridae family, etc.) represents a missed opportunity, given the importance of this issue for the clinical virologist and the wealth of data available from other sources.

In summary, the manual provides much useful information to the practitioner managing a diagnostic virus laboratory; however, the value of the book as a strategic guidance for clinical virology appears to be limited.