Specimen Collection

• Pulmonary tuberculosis: threat to both patients and others so sample should be collected and handled in a safe manner.
• Successful identification of pathogens depends on quality of the specimens and appropriate processing of samples.
• Pulmonary secretion: sputum, gastric lavage, tracheal aspirate, bronchospcopic aspirations
• Sputum: most important and frequently received
• Container: wide mouth, sterile, clean, leak proof, labeling site and placed into bags to stop leakage
• Specimen of choice: spontaneously induced sputum
• Patients is instructed to take deep breath, hold for few seconds and then cough deeply and vigorously
• Covering mouth during coughing to prevent spread of aerosols
• Not to use oral antiseptics before collection
• Rejected samples: saliva, nasal secretions, specimen containing food particles and other matters
• Aerosol induction technique: saline aerosol induction procedure to induce sputum from those patients who can not produce sputum spontaneously.
• Saline aerosol, causes irritation, when inhaled slowly, induces deep coughing and facilitates sputum collection

Gastric lavage specimen

• Collected form those patients who have swallowed sputum during night
• Procedure is limited to senile, non ambulatory and children younger than 3 years old
• Levine collection tube is inserted through the nose , when fully inserted, a syringe is attached to the end of the tube and filtered distilled water is inserted through tube
• 20-25 ml gastric lavage specimen is then collected
• Series of specimen should be collected within 3 days

Urine samples

• Early morning voided urine (EMU) sample should be collected
• Whole sample should be sent for examination
• Twenty four hour urine sample are undesirable because of excessive dilutions, higher contamination and difficulty in concentration

Body fluids

• Tubercular meningitis, rather uncommon, may in immunocompromised patients
• At least 10 ml of CSF and 10-15 ml of peritoneal, pericardial sample is collected
• Pleural fluid and ascitic fluid tend to clot so should be collected in a tris sodium citrate container

Blood

• Immunocompromised patient particularly co-infected with HIV may have disseminated mycobacterial infection
• collected in a manner as for routine blood culture
• Best recovery in BACTEC vial or isolator – centrifugation system

Feces

• Clean, dry, wax free container without any diluents

Pus

• Skin should be cleaned using alcohol
• collected in a syringe or swab depending upon the volume

Transportation

• Specimen should be promptly delivered to laboratory and can be refrigerated if processing is delayed (only for sputum, gastric lavage and urine)
• Should be labeled as HIGH RISK
• Specimen should be opened in Class II containment