Sputum Analysis

• Sputum


  Material coughed up from the alveoli, bronchi, and trachea of the pulmonary tree. It is an exudate which is formed during pulmonary or tracheal infections. It is composed of secretions, exudations, and exfoliations of the bronchopulmonary tree.
• Under normal conditions, mucous secretions of the goblet cells and mucous glands associated with the respiratory epithelium are carried by the ciliated epithelium up to trachea and swallowed unnoticed, this, however, is insufficient to stimulate coughing and expectoration
• Any irritation of the bronchial tree incites the cough reflex causing and forcing the mucous and other pulmonary secretions from the upper trachea to the mouth which is then expectorated
• Sputum analysis


  Important in detecting neoplastic diseases of the lungs and other respiratory organs, detecting the occurrence of upper respiratory tract infections, allergic reactions or inflammation and the causative agents of such diseases, and as a guide in selection of appropriate therapy for disease agent
• Sputum


  Mucous/Thick fluid/Expectorated matter that is produced in the lungs and in airways that lead to the lungs. Mixture of plasma, electrolytes, mucin, water, cellular exfoliations, nasal and salivary secretions, bacterial flora. Some of the diseases can cause pus, blood, or bacteria to show up in the sputum.
• Specimen of choice for sputum analysis

  • Morning specimen
  • 24-hour specimen
• Throat swab


  For pediatric patients
• Tracheal aspiration


  For debilitated patients
• Respiratory system


  • Divided into upper (structures above the larynx) and lower respiratory tract (structures below the larynx, through the trachea, to the bronchi and bronchioles, and then into the alveolar spaces where gas exchange occurs)
  • Exposed to the outside environment, possesses a series of defenses, natural barriers, against inhaled materials
• Filtration of air in the respiratory system


  1. Large particles filtered out by cilia and mucus in the nasal cavity

  2. Further filtration as air passes over cilia and mucus in the trachea

  3. Coughing aids in clearance and expulsion of particulate matter

  4. Macrophages ingest organisms, polymorphonuclear and monocytes recruited once lungs become inflamed
• Lower respiratory tract (LRT)


  Structures below the larynx, including the trachea, bronchi, bronchioles, and alveoli
• Sputum


  Material coughed up from the alveoli, bronchi, and trachea of the pulmonary tree. Composed of secretions, exudations, and exfoliations of the bronchopulmonary tree.
• Pneumonia


  • Inflammation of the LRT involving the lung's airways and supporting structures
• Pathogenesis of pneumonia


  1. Upper airway colonization

  2. Aspiration of organisms

  3. Inhalation of airborne droplets containing the organism

  4. Seeding of the lung via the blood from a distant site of infection

  5. Viruses cause primary infection of the LRT, inhibit host defense leading to secondary bacterial infection
• Symptoms of pneumonia


  Fever, chills, chest pain, and cough
• Major groups of pneumonia (in the past)

  • Typical/acute pneumonia
  • Atypical pneumonia
• Major categories of pneumonia (present time)


  • Community-acquired pneumonia (CAN)
  • Hospital or ventilator or health-care associated pneumonia
• Most common causes of community-acquired viral pneumonia in children

  • Respiratory Syncytial Virus (RSV)
  • Parainfluenza
  • Influenza
  • Adenovirus
• Most common bacterial pathogens causing pneumonia

  • Infants and children: Streptococcus pneumoniae
  • Young adults: Mycoplasma pneumoniae
  • Adults: Streptococcus pneumoniae
• Most common causes of viral pneumonia in adults

  • Respiratory Syncytial Virus (RSV)
  • Parainfluenza
  • Influenza
  • Adenovirus
  • Coronavirus
  • Rhinovirus
• Most common causes of fungal pneumonia in adults

  • Actinomyces
  • Nocardia
• Complications of community-acquired pneumonia (CAN)

  • Parapneumonic effusions
  • Empyema
  • Respiratory failure including need for mechanical ventilation
  • Acute respiratory distress syndrome (ARDS)
  • Septic shock with multisystem organ failure
• Pneumonia in patients with neoplasms

  Prone to pneumonia due to granulocytopenia, and cellular and humoral dysfunction
• Pneumonia in transplant recipients

  Recipient's immune system must be suppressed for successful organ transplantation
• Pneumonia in HIV patients/HIV infected patients

  Most common causes are Pneumocystis jirovecii and Mycobacterium tuberculosis (most likely etiologic agent for chronic lower respiratory infections)
• Acute bronchitis


  Acute inflammation of the tracheobronchial tree, may be part of or preceded by an upper respiratory tract infection, characterized by cough, fever, and sputum production
• Chronic bronchitis


  Common condition affecting 10 to 25 percent of adults, defined by clinical symptoms of excessive mucus production leading to coughing up sputum on most days during at least three consecutive months for more than 2 successive years
• Bronchomoniliases


  Infection of the bronchi with fungi of the genus candida
• Bronchiolitis


  Inflammation of the smaller diameter bronchiolar epithelial surfaces, acute viral lower respiratory tract infection that primarily occurs during the first 2 years of life, characterized by acute onset of wheezing, hyperinflation, cough, rhinorrhea, tachypnea, and respiratory distress
• Parts of the pharynx

  • Nasopharynx
  • Oropharynx
  • Laryngopharynx
• Pharyngitis


  "Sore throat"
• Major causes of pharyngitis

  • Children: Group A beta-hemolytic Streptococci (Streptococcus pyogenes)
  • Adults: Usually caused by a virus
• Complications of untreated streptococcal pharyngitis

  • Can travel to the kidneys and cause poststreptococcal acute glomerulonephritis
  • Can travel to the heart and cause Acute Rheumatic heart fever
• Collection of sputum specimen

  1. Patient brushes teeth and rinses mouth to avoid contamination

  2. Cough up sputum from deep down the throat into a sterile container

  3. Early morning specimen preferred as it contains greater concentration of bacteria

  4. 24-hour specimen satisfactory for detecting tubercle bacilli
• Procedure in collecting expectorated sputum

  1. Brush teeth and rinse mouth

  2. Avoid mixture of saliva

  3. Cough up sputum into culture tube or container

  4. Cap must be tightly closed

  5. Avoid contaminating outside of container

  6. Early morning specimen is preferable

  7. 24-hour specimen is satisfactory for tuberculosis
• Induced sputum


  For patients unable to produce sputum, using postural drainage and thoracic percussion to stimulate production
• Induced sputum collection


  1. Allow patient to breathe aerosolized droplets using a nebulizer containing 10% NaCl or 10% propylene glycol

  2. Patient coughs and sputum is collected
• Endotracheal or tracheostomy suction specimens


  For patients with tracheostomy who cannot produce sputum normally, lower respiratory tract secretions can be collected in a Lukens trap/Sputum trap
• Bronchoscopy specimens


  Bronchoalveolar lavage (BAL), bronchial washing, bronchial brushing, transbronchial biopsies
• Bronchoalveolar lavage


  High volume of sterile saline (100-300 mL) infused into lungs in 20-50 mL aliquots, first aliquot discarded, remaining aliquots analysed