Published on LMS

For sputum smear microscopy, the slides should be air-dried as heating the slide while the smear is wet can result in bubbling of TB bacilli into the air.

Fixation makes the sputum stick to glass slide and preserves the shape of the bacilli. 

The procedure for air-drying and heat-fixing the slide is as follows:

Storage conditions of sputum sample can effect the test results.

• Sputum samples should be transported to the laboratory as soon as possible after collection.
• It is the responsibility of Laboratory Technician (LT) and Senior TB Laboratory Supervisor (STLS) to ensure proper storage and transport of sputum specimens.
• Sputum is stored to preserve the specimen quality.
• The stored sputum samples should not be frozen.

Storage of Sputum Samples

For microscopy

The binocular microscope requires considerable care in its use, regular cleaning, and protection from dust and fungal growth.

Annual maintenance of a microscope includes:

Regular cleaning of microscope is essential to ensure that it is optimally functioning. Cleaning is important to remove dirt, lens immersion oil and ensure disinfection. It involves cleaning the lenses, the body, the stage of the microscope and the light source. The microscope needs to be cleaned daily and the lenses need to be cleaned after each use.

Materials used for cleaning:

Proper handling, maintenance and storage of the microscope are essential for proper functioning and life of the microscope.

The microscope should be placed and stored preferably in a box in a dry, dust-free and vibration-free environment, which is specially built in the laboratory (as shown in the figure below).

Removable parts in a microscope that need replacement include objectives, eyepieces, light bulbs, fuses. In case of repair/ technical support, only competent agency that handles maintenance of instruments should be contacted. Laboratory personnel should never attempt to dismantle any part of the microscope for repair.

Some of the common technical problems encountered, their likely causes and solutions are given in the table below.

Peripheral Health Care Workers (PHWs) including Community Health Officer (CHO), Auxiliary Nurse Midwife (ANM) and Multi-purpose health worker (MPHW) are central to primary health care and service delivery. They play important an role in TB care at Peripheral Health Institutes (PHIs) and Designated Microscopy Centres (DMCs).

Their responsibilities include:

1. Vulnerable population mapping: vulnerability assessment and mapping of vulnerable population (diabetic patients, patients on immunosuppressants, alcoholics and smokers etc) in communities is done by PHWs.

To increase access to diagnostic services, NTEP has a provision for sputum collection centres in areas where the health facility is not equipped with key requirements to conduct sputum microscopy, molecular tests, drug susceptibility testing or follow up examinations.

Sputum collection centres are dedicated locations where sputum samples are collected, packaged and then transported to nearby TB diagnostic centres. It could be attached to any near-by health-facility as well.

Requirements of a Sputum Collection Centre

The Medical Officer Designated Microscopy Centre (MO-DMC) at a Primary Health Facility is appointed from the General Health System. The MO-DMC is responsible for activities at DMC under the National TB Elimination Programme (NTEP).

Key Responsibilities of MO-DMC include

1. Screening and diagnosis

·        Clinical examination of all TB cases should be done by the MO. 

• Egyptian mummies, dating back to 2400 BC, reveal skeletal deformities typical of tuberculosis; characteristic of Pott's lesion.
• In Ancient Greece, TB was called Phthisis. Hippocrates described Phthisis as a fatal disease and accurately defined its symptoms and characteristic tubercular lung lesions.
• In 1700s, TB was called “the white plague” due to the paleness of the affected patients.
• In 1793, the Scottish pathologist, Matthew Baille named the caseous necrosis, "cheese-like", phthisic abscesses as "tubercles".