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

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

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

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

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