Collecting a Sputum Sample Good quality sputum specimens Patient and staff safety Sputum smear microscopy remains the most reliable and cost-effective way of identifying infectious cases of TB. This is critical for TB control which relies on the prompt identification and treatment of infectious cases in order to reduce the pool of infection and therefore transmission within the community. Hence it is important than sputum specimens are collected using the best practice outlined in this standard.

Preparing to get a sputum sample Sputum testing starts during the first consultation with the patient. This is when the patient first comes to the clinic or unit. The explanation of how to produce a good sputum sample, why is it needed and actual production of the sample needs to take place in a private, well-ventilated and confidential space. The patient may be very nervous at this stage and feel bombarded with information. It is important to check that the patient understands the process and can bring up any problems he or she might foresee. There is a real risk that the patient may not return future specimens if he or she feels unwelcome or confused. Beginning to develop a good relationship with the patient at this stage will help to ensure his or her cooperation in the future.

The nurse explains to Mercy why she needs a sputum sample Sputum testing starts during the first consultation with the patient. This is when the patient first comes to the clinic or unit. The explanation of how to produce a good sputum sample, why is it needed and actual production of the sample needs to take place in a private, well-ventilated and confidential space. The patient may be very nervous at this stage and feel bombarded with information. It is important to check that the patient understands the process and can bring up any problems he or she might foresee. There is a real risk that the patient may not return future specimens if he or she feels unwelcome or confused. Beginning to develop a good relationship with the patient at this stage will help to ensure his or her cooperation in the future.

Why are two sputum specimens needed? Two samples help ensure patients found to be positive for TB are not missed. Initial specimen – positive for 83-87% of all patients Second specimen- positive for 10-12% of all patients The optimum number of sputum specimens to establish a diagnosis has been examined in a number of studies. In a recent review of data from a number of sources, it was stated that, on average, the initial specimen was positive in about 83–87% of all patients ultimately found to have acid-fast bacilli detected, in an additional 10–12% with the second specimen, and in a further 3–5% on the third specimen. A rigorously conducted systematic review of 41 studies on this topic found a very similar distribution of results: on average, the second smear detected about 13% of smear-positive cases, and the third smear detected 4% of all smear-positive cases. In studies that used culture as the reference standard, the mean incremental yield in sensitivity of the second smear was 9% and that of the third smear was 4%. Hence it is important to take two sputum specimens for each patient.

Mercy rinses her mouth before the sputum sample is collected The patient is encouraged to rinse their mouth with water, especially if they have been eating food, before expectorating into the container. If the sample is mixed with food particles, it may make it difficult for the microbiologist to present an accurate report of the diagnosis.

Picture 4 – Mercy and HCP are standing in front of a window The health-care worker supervises the collection, but without standing in front of the person attempting to produce the sputum. Ideally, there should a separate well-ventilated area for sputum collection, preferably outside the building, avoiding use of the toilets. You need to ensure that patient’s privacy is maintained hence standing outside may not be possible. It is imperative you use well-ventilated area for producing a sample, such as near a window as shown in this picture

Nurse demonstrates how to cough for a sputum

Ensuring privacy and ventilation The nurse puts a screen in the room to ensure Mercy’s privacy is maintained when she is coughing up the sputum sample. And she opens the room door behind the Screen, so there is enough ventilation in the room.

Infection control precautions: handling the specimen You must wear gloves when handling the sputum sample. The specimen must be handled carefully and the lid closed tightly to prevent transmission. The patient must be informed about the importance to close the lid tightly and avoid coughing outside the specimen pot, when producing the second sputum sample at home.

The specimen As Good specimen contains approximately 3-5 mls of solid or purulent material. This means about a teaspoon full of sputum sample is sufficient. This specimen is required to give the laboratory technician the best chance of seeing AFBs under the microscope and therefore for the service to identify the most infectious patients. If the sample is inadequate or it is only saliva, it may not be possible to see AFBs even if the patient is infectious. The specimen is checked by the health-care worker with the patient present – if it is insufficient the patient is asked to cough again and add to it.

Addressing Mercy’s anxieties