Bronchitis laboratory tests
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]Associate Editor(s)-in-Chief: Seyedmahdi Pahlavani, M.D. [2]; Nate Michalak, B.A.
|
Bronchitis Main page |
Overview
Diagnostic tests are rarely needed to confirm the diagnosis of acute bronchitis. In very specific conditions, serologic tests, viral cultures or sputum analyses may be performed. Generally, inflammatory markers, such as C-reactive protein, rise during the course of acute bronchitis. Chronic bronchitis is diagnosed by definition, although there are some laboratory findings as the disease advances and causes complications.
Laboratory Findings
Acute Bronchitis
Viral cultures, serologic assays, and sputum analyses may be performed when a potentially treatable infection is thought to be circulating or because of epidemiological purposes.[1]
- Serologic assays
- Nasopharyngeal swab and aspirates to test for PCR are available but not widely used.[1]
- Procalcitonin
- Procalcitonin level is helpful to distinguish bacterial from other causes of inflammation. During bacterial infections, the level of procalcitonin will rise over 0.25 mg/L and indicates prescription of antibiotics.[2][3][4]
Chronic Bronchitis
- Pulse Oximetry
- Although pulse oximetry is not as accurate in predicting the percent oxygen saturation as arterial blood gas analysis, it gives a quick estimate of patient status when considered with the clinical status.
- Arterial Blood Gas (ABG)
- ABG may show changes of hypoxemia and hypercapnia depending on the severity of disease.
- Hematocrit
- COPD patients may have hypoxemia due to the chronic underlying disease. This chronic hypoxemia may lead to polycythemia.
- Hematocrit > 55% in men or 50% in women is diagnostic of polycythemia.
- COPD patients may have hypoxemia due to the chronic underlying disease. This chronic hypoxemia may lead to polycythemia.
- Culture
- A sputum sample showing neutrophil granulocytes and culture showing pathogenic microorganisms such as Streptococcus spp.
- Alpha 1 Antitrypsin Levels[5]
- Serum alpha 1 antitrypsin levels below the protective threshold value (i.e. 3-7 mmol/L) may lead to a severe form of emphysema
- 95% cases are due to the severe variant the Z allele present in these patients.
- Specific phenotyping, and genetic counseling is reserved for patients in whom serum levels are 7-11 mmol/L.
References
- ↑ 1.0 1.1 Wenzel RP, Fowler AA (2006). "Clinical practice. Acute bronchitis". N. Engl. J. Med. 355 (20): 2125–30. doi:10.1056/NEJMcp061493. PMID 17108344.
- ↑ Schuetz P, Christ-Crain M, Thomann R, Falconnier C, Wolbers M, Widmer I, Neidert S, Fricker T, Blum C, Schild U, Regez K, Schoenenberger R, Henzen C, Bregenzer T, Hoess C, Krause M, Bucher HC, Zimmerli W, Mueller B (2009). "Effect of procalcitonin-based guidelines vs standard guidelines on antibiotic use in lower respiratory tract infections: the ProHOSP randomized controlled trial". JAMA. 302 (10): 1059–66. doi:10.1001/jama.2009.1297. PMID 19738090.
- ↑ Briel M, Schuetz P, Mueller B, Young J, Schild U, Nusbaumer C, Périat P, Bucher HC, Christ-Crain M (2008). "Procalcitonin-guided antibiotic use vs a standard approach for acute respiratory tract infections in primary care". Arch. Intern. Med. 168 (18): 2000–7, discussion 2007–8. doi:10.1001/archinte.168.18.2000. PMID 18852401.
- ↑ Gilbert DN (2011). "Procalcitonin as a biomarker in respiratory tract infection". Clin. Infect. Dis. 52 Suppl 4: S346–50. doi:10.1093/cid/cir050. PMID 21460294.
- ↑ "American Thoracic Society/European Respiratory Society statement: standards for the diagnosis and management of individuals with alpha-1 antitrypsin deficiency". Am. J. Respir. Crit. Care Med. 168 (7): 818–900. 2003. doi:10.1164/rccm.168.7.818. PMID 14522813.