In the case of only short-term sputum in the context of acute inflammation of the upper respiratory tract, laboratory diagnostics are usually not necessary.
2nd-order laboratory parameters-depending on the results of the history, physical examination, and obligatory laboratory parameters-for differential diagnostic workup
- Small blood count
- Differential blood count
- Inflammatory parameters – CRP (C-reactive protein) or ESR (erythrocyte sedimentation rate).
- Bacteriologic examination of sputum, tracheal secretions/pharyngeal swab (nasopharyngeal swab if sputum cannot be produced; bronchial lavage (flushing of bronchi for diagnostic purposes) – if microbial cause is suspectedNote: Send only macroscopically purulent sputum specimens or other deep respiratory materials. Sputum should be obtained by vigorous coughing – preferably in the morning.
- Allergy diagnostics
- Sputum cytology – if bronchial carcinoma (lung cancer) is suspected.
- Biopsy (tissue sample) – for histological / fine tissue examination.
- Molecular genetic testing – for suspected cystic fibrosis.
Notes on preanalytics in sputum diagnostics.
- Correct collection, i.e. rinse mouth before sputum collection; do not give “spit” but only highly coughed material.
- Forwarding of the sample material within max. 2 hours; best refrigerated, then forwarding within max. 4 hours.
