Recomendaciones Del Grupo De Trabajo Enfermedades Infecciosas (GTEI) De La Sociedad Española De Medicina Intensiva, Crítica Y Unidades Coronarias (SEMICYUC) Y El Grupo De Estudio De Infecciones En El Paciente Crítico (GEIPC) De La Sociedad Española De Enf

The diagnosis of influenza A/H1N1 is mainly clinical, particularly during peak or seasonal flu outbreaks. A diagnostic test should be performed in all patients with fever and flu symptoms that require hospitalization. The respiratory sample (nasal or pharyngeal exudate or deeper sample in intubated patients) should be obtained as soon as possible, with the immediate start of empirical antiviral treatment. Molecular methods based on nucleic acid amplification techniques (RT-PCR) are the gold standard for the diagnosis of influenza A/H1N1. Immunochromatographic methods have low sensitivity; a negative result therefore does not rule out active infection. Classical culture is slow and has low sensitivity. Direct immunofluorescence offers a sensitivity of 90%, but requires a sample of high quality. Indirect methods for detecting antibodies are only of epidemiological