One of the main reasonss that some countries require a medical examination before granting a visa is screening for serious communicable diseases, tuberculosis (TB) being chief among them. Over 10 million people worldwide fall ill with TB every year and 10% of them die. Some countries have a much higher prevalence of TB than others. These are mostly in Southeast Asia, Western Africa and some parts of Eastern Europe.
The simplest method of screening for TB is an old fashioned chest X-ray. In our experience as Panel Physicians, about 2% of all immigrants we see have some chest X-ray findings that justify a suspicion of latent TB infection (LTBI).
This suspicion is expressed by the radiologist that reads the X-ray and, once submitted to Immigration, it is then reviewed by the medical personnel there. We then get a "Medical Furtherance" request from them, asking us to arrange further investgations. These always include some combination of repeat X-rays and sputum tests, sometimes also a specialist opinion.
Sputum is a thick dischage from the bronchial tree. Healthy nonsmokers do not normally produce any sputum. However, with patience and a special technique, it is possible to produce a sample that contains a small amount of bronchial content.
Please watch this video for complete instructions:
youtube.com/watch?v=rIQDP41Qd8s
You may also want to check this video, produced by our provincial TB Control:
youtube.com/watch?v=EBOrSNvE53, but the first video has a better demonstration of the technique.
The key points are:
Results are reported in two stages. First, we get “smear” results after about a week. This is a direct microscopic examination of your sample, looking for the tubercle bacillus. If it is present, it indicates an active infection and treatment can start st this point.
If the smears are negative, it still does not rule out a mild latent infection. The sample is incubated for 6 weeks, attempting to grow any hidden bacillus. If there is no growth, it is strong evidence that you do not carry the bacillus. Three samples collected on different days are required to increase the confidence in the results. However, even that is not absolute and a followup chest X-ray in 3 months is usually also required. If there is no interval change between the first and second X-ray, that is the final and sufficient proof that you are free of TB.
If you absolutely cannot produce sputum, some authorities will accept a followup X-ray at 6 months, instead of the combination of sputum cultures plus X-ray at 3 months.
In very special cases, some rather extreme methods can be used to collect sputum, such as using an apparatus that produces vibrating air waves and loosens sputum, or by direct bronchial washing under anesthesia. But, do not worry - these are never used in immigration cases.
