PT  - JOURNAL ARTICLE
AU  - L J van Elden
AU  - G A van Essen
AU  - C A Boucher
AU  - A M van Loon
AU  - M Nijhuis
AU  - P Schipper
AU  - T J Verheij
AU  - I M Hoepelman
TI  - Clinical diagnosis of influenza virus infection: evaluation of diagnostic tools in general practice.
DP  - 2001 Aug 01
TA  - British Journal of General Practice
PG  - 630--634
VI  - 51
IP  - 469
4099  - http://bjgp.org/content/51/469/630.short
4100  - http://bjgp.org/content/51/469/630.full
SO  - Br J Gen Pract2001 Aug 01; 51
AB  - BACKGROUND: With the development of new antiviral agents for influenza, the urge for rapid and reliable diagnosis of influenza becomes increasingly important. Respiratory virus infections are difficult to distinguish on clinical grounds. General practitioners (GPs) however, still depend on their clinical judgement. AIM: To evaluate the importance of clinical symptoms in the diagnosis of influenza virus infection. DESIGN OF STUDY: A multicentre questionnaire study. SETTING: Eighty-one patients from 14 general practices. METHOD: Patients with fever and at least one constitutional symptom and one respiratory symptom were included. A questionnaire with the medical history and clinical symptoms was completed and a combined nose-throat swab was taken. Virus culture, rapid culture, and polymerase chain reaction (PCR) amplification were performed on each specimen. Multivariate analysis was used to obtain the best predictive model. RESULTS: By using PCR, an increase was seen in the detection of the viral pathogens compared with the results of culture. In 42 out of 81 patients PCR was positive for influenza. A positive predictive value (PPV) of 75% was observed for the combination of headache at onset, feverishness at onset, cough, and vaccination status during the period of increase influenza activity. Criteria used by the ICHPPC-2 resulted in a PPV of 54%. The PPV for diagnosis made by the GP was 76%. CONCLUSION: Although influenza is difficult to diagnose on clinical grounds, the GPs in this study were able to diagnose influenza as such more accurately on their judgement than by the other criteria.