What is TB disease?

TB disease develops when the immune system cannot keep tuberculosis bacteria under control, and bacteria begin to rapidly multiply and destroy tissue in the body: the bacteria can actually create a cavity or hole in the lung. People with TB disease are sick, and usually have symptoms.

TB disease can develop very soon after infection, or may appear many years after infection. People with TB disease can spread TB to others.

People with TB Disease:

  • Usually have signs and symptoms
  • Usually feel sick
  • May spreads TB bacteria to others
  • Usually have a positive TB test
  • May have an abnormal chest x-ray, or positive sputum smear or culture
  • Need treatment to stop the disease

TB disease normally affects the lung and is known as pulmonary TB. When TB occurs outside the lung it is referred to as extra-pulmonary TB. TB in the lungs or throat can be infectious, meaning the bacteria can be spread to other people. People with TB disease are most likely to spread it to those they spend time with every day, including family members, friends, coworkers, classmates, commuters, etc. TB disease in other parts of the body – such as the kidney or spine – is usually not easily spread to others.

The likelihood that TB will be transmitted heavily depends on the following factors.

  • Infectiousness of the person with TB disease
  • Environment in which exposure occurred
  • Duration of exposure
  • Virulence of the organism

What is TB?

Tuberculosis (TB) is a bacterial disease of public health concern. It spreads through the air when a person with TB disease coughs, sneezes, laughs, sings, or even speaks. TB most often affects the lungs, but can spread to other parts of the body. If improperly treated or left untreated, TB can be fatal.

How does TB spread?

TB is spread through the air from one person to another. The TB bacteria are released into the air when a person with TB disease coughs, sneezes, speaks or sings. People nearby may inhale these bacteria and become infected. . Although anyone can be exposed to TB disease, certain groups are at higher risk for exposure, including health care professionals, the homeless, people in congregate settings and individuals from countries where TB is highly prevalent like Kenya.

TB is NOT spread by

  • Shaking someone’s hand
  • Sharing food or drink
  • Touching bed linens or toilet seats
  • Sharing toothbrushes
  • Kissing

What are the symptoms of TB?

The general symptoms of TB disease include

  • Unintentional Weight loss
  • Fever
  • Drenching Night sweats.
  • Cough of any duration

For Children below 5 years

  • Irritability
  • Failure to thrive
  • Reduced playfulness
  • History of contact with a TB case

Symptoms of TB disease occurring outside of the lungs depend on the area affected.

Note: Since symptoms of TB usually start gradually, often TB is not suspected, or is misdiagnosed as another illness.

How is TB disease treated?

A person with TB infection needs to take TB Preventive Therapy (TPT) in order to kill the TB bacteria and prevent progression of TB infection to TB disease.. Some people are more likely than others to develop the disease once they have the infection. This includes people with HIV infection, people who were recently exposed to someone with TB disease, smokers, people with certain medical conditions such as diabetes and kidney problems, and persons taking immunosuppressive drugs.

Treatment for TB infection requires two drugs given in one directly observed dose per week, for 12 weeks. Other single drug treatment options take from six to nine months to complete.

What is TB Infection?

When a person is diagnosed with TB infection, it means that they have been exposed to the disease and have become infected with it. About 5% of infected people progress to TB disease within the first two years after becoming infected. Another 5% will develop disease later in life. People who are infected:

  • Have no symptoms
  • Don’t feel sick
  • Cannot spread TB to others
  • Usually have a positive TB skin test or TB blood test (Interferon Gamma Release Assay)
  • May develop TB disease if not treated for TB infection

People at greater risks of progressing to TB disease usually have a weakened immune system. Older people; children under the age of 5; people with chronic illness (especially diabetes), lung diseases, certain cancers; those who smoke, abuse substances, or take immunosuppressive medications and those with HIV infection have much higher risk of developing TB disease if not treated.
Sometimes people are given treatment to prevent TB infection from progressing to TB disease even if their TB test is negative. This is often done with all HIV infected patients and children or adults who are contacts of confirmed TB patients. These groups are at high risk of developing TB disease soon after they are exposed to TB bacteria. If you are prescribed treatment for TB infection, it is important that you take all of your pills exactly as prescribed. Remember to regularly follow up with your healthcare provider, while on medication so they can monitor your progress.

How is TB infection treated?

A person with TB infection needs to take TB Preventive Therapy (TPT) in order to kill the TB bacteria and prevent progression of TB infection to TB disease.. Some people are more likely than others to develop the disease once they have the infection. This includes people with HIV infection, people who were recently exposed to someone with TB disease, smokers, people with certain medical conditions such as diabetes and kidney problems, and persons taking immunosuppressive drugs.

Treatment for TB infection requires two drugs given in one directly observed dose per week, for 12 weeks. Other single drug treatment options take from six to nine months to complete.

What is TB exposure?

Exposure occurs when a person shares air with someone who has active infectious TB disease. You may have been exposed to TB if you spent time near someone with TB disease of the lungs or throat. You can only get infected by breathing in TB bacteria that a person expels into the air.

You cannot get TB from someone’s clothes, drinking glass, eating utensils, handshake, toilet, or other surfaces where a TB patient has been. Most people are never exposed to a person with active infectious tuberculosis disease for a period long enough to become infected. People most likely to become infected are those that share air with a TB patient for a prolonged period of time either in a single or group setting. Individuals more likely to be exposed to TB include health care workers, the homeless, persons living or working in congregate or long-term care facilities, and persons traveling to or living in countries with high TB prevalence. A TB Interferon Gamma Release Assay (blood test) and Tuberculin Skin Test (TST) will identify TB infection.

Is TB infection dangerous?

Untreated, TB infection can progress to TB disease. A person with TB infection does not feel sick and has no symptoms. Persons with TB infection cannot spread the infection to others. A TST or blood test can detect the presence of TB infection. TB infection should be treated to prevent it from progressing to TB disease which can be spread to others.

How can I be tested for TB?

You can be tested for TB infection through tuberculin skin test and blood test in a health facility of your choice. The tests are quick and simple, and give results in only a few days. TB disease can be diagnosed by sputum test or any other sample(microscopy, Gxpert, True Nat) which is a preferred diagnostic test.

What is the GeneXpert test?

The GeneXpert test is a molecular test for diagnosing TB. It is often the first test to be done in countries with a high rate of TB disease. The GeneXpert diagnosis TB by detecting the presence of TB bacteria, as well as testing for rifampicin drug resistance. True Nat is another molecular test that can be used to diagnose TB.

Sputum smear microscopy as a test for TB

Smear microscopy of sputum is often the second test to be used in countries with a high rate of TB.

To do the test a smear is prepared by applying a thin layer of the sample on a glass slide. A series of special stains are then applied to the sample, and the stained slide is examined under a microscope for TB bacteria.

What is sputum?

Sputum is mucous that you cough up from deep inside your lungs. It is usually thick, cloudy and sticky. Sputum is not saliva (spit). Saliva comes from your mouth and is thin, clear and watery. Do not collect saliva for this test.

Why should I do a sputum test for TB?

Testing your sputum for TB disease can show the bacteria in the sputum and it’s the best way to find out if you have TB disease.

If you are taking medicine for TBdisease, testing your sputum is the best way to tell if the medicine is working
Other samples(lymph node aspirate pleural/pericardial fluid, pus, cerebral spinal fluid etc) can also be used to diagnose TB

Why do I have to collect more than one sample?

It is very important that the results from your sputum test are accurate. Collecting multiple samples can improve the accuracy of your test results. Your health care provider will let you know if you can collect multiple samples on the same day or if you should collect the samples on separate days. Follow the instructions your health care provider gives you.

How do I collect sputum?

To collect sputum, follow these steps:

  1. Collect your sputum early in the morning unless your health care provider gives you different instructions.
  2. Do not eat, drink, smoke, brush your teeth, or use mouthwash before collecting your sputum.
  3. Verify that your first name, last name, and date of birth are on the label of the sample bottles.
  4. Collect your sputum away from other people. If possible, go outside or open the windows while you collect your sputum.
  5. Open a sample bottle. Do not touch inside the sample bottle or inside the cap.
  6. Take a deep breath. Hold your breath for a few seconds. Breathe out slowly. Take another deep breath. Cough hard until sputum comes up in your mouth.
  7. Spit the sputum into the sample bottle. Do this until there is enough sputum to cover the bottom of the bottle.
  8. Screw the cap on the sample bottle tightly so it does not leak.
  9. Seal the sample bottle in the plastic bag it came with. Do not put more than one sample bottle in each plastic bag.
  10. After you finish collecting your sputum, wash your hands.

What is the incubation period of tuberculosis?

From infection to development of a positive TB test (the incubation period) can take 2 to 10 weeks. The risk for developing active disease is the highest in the first two years after infection. If not treated, a risk continues throughout your lifetime.

What is a TB contact?

A person who has shared the same enclosed living space with a person with confirmed TB disease for one or more nights; or for frequent or extended daytime periods during the 3 months before the start of the current treatment. TB contacts are ranked from high to low priority. High priority means either the person has had prolonged exposure, or that the person is highly susceptible to becoming infected and progressing to TB disease — children under the age of 5 or persons infected with HIV or on immunosuppressive therapy. Contacts should be promptly tested once exposure is known and tested again about 10 weeks after the last known exposure. If either test is positive, the person is considered infected and requires additional follow-up and treatment.

What is Extensively Drug Resistant Tuberculosis (XDR-TB)?

Extensively drug resistant TB (XDR-TB) is a relatively rare type of DR-TB. XDR-TB is defined as TB which is resistant to isoniazid and rifampin, plus resistant to any fluoroquinolone and at least one of three injectable second-line drugs (i.e., amikacin, kanamycin, or capreomycin). Because XDR-TB is resistant to first-line and second-line drugs, patients are left with treatment options that are much less effective and may require prolonged treatment.

What is Multi-Drug Resistant Tuberculosis (MDR-TB)?

Multidrug resistant TB (MDR-TB) is a tuberculosis disease in which the TB bacterium is resistant to both isoniazid and rifampin, the two strongest anti-tuberculosis medications. TB can become resistant to antibiotics when the drugs are misused or mismanaged, when patients do not complete their full course of treatment, when healthcare providers prescribe the wrong treatment, the wrong dose, or length of time for taking the drugs; or when the drugs are of poor quality. Treating MDR-TB is complicated and involves the use of second-line medications that carry greater risk of side effects and adverse reactions. Patients taking these drugs must be monitored closely throughout the course of treatment. The regimen usually requires at least 18-24 months and must be individualized based upon the patient’s medical history. Treatment for patients co-infected with HIV can be more complicated, usually further lengthening treatment time.

Who should be tested?

You should get a TB test if:

  • You have spent time with a person who has active TB.
  • You have the symptoms of TB: coughing, pain in the chest, coughing up blood, and fatigue.
  • You have a chronic disease such as diabetes, or another condition that weakens the immune system.
  • You have lived or worked in a place where TB is common: migrant farm camps, prisons, homeless shelters or other crowded places where disease can spread.
  • You use drugs injected with needles that may not be sterile.
  • You have HIV infection.

When will I get the results from my sputum tests?

Smear test results are usually ready within 1 to 2 business days after it arrives at the lab. Culture results may take up to 8 weeks, depending on how quickly the bacteria grow.

The laboratory will notify your health care provider of your test results as soon as they are ready. If your test results are positive, your health care provider will let you know.

Be sure that your healthcare provider knows how to reach you to give you your test results. Check with your health care provider to make sure they have your current phone number and address.

If you have any questions or concerns, speak with your healthcare provider.

What tests will be done on my sputum?

Two tests will be done on your sputum:

  • GeneXpert
  • Smear
  • Culture (For the culture, laboratory staff put some of your sample into a special container to grow. If bacteria grow, your culture result is positive).
  • If the results from tests above are positive, your health care provider will talk with you about what this result means.

What should I do with the sample bottles after I have collected my sputum?

Take the sample bottles to the lab or your health care provider as soon as possible. Store the sample bottles in the fridge until you are able to take them to the health facility.. Do not store the sample bottles at room temperature nor let the sample bottles freeze.

If you are not sure where to return the sample bottles , ask your healthcare provider.

Why Use Daily Observed Therapy (DOT)


  • We cannot predict who will take medications as directed, and who will not. People from all social classes, educational backgrounds, ages, genders, and ethnicities can have problems taking medications correctly.
  • Studies show that 86-90% of patients receiving DOT complete their therapy, compared to 61% for those on self-administered therapy.
  • DOT helps patients finish TB therapy as quickly as possible, without unnecessary gaps.
  • DOT helps prevent TB from spreading to others.
  • DOT decreases the risk of drug-resistance resulting from erratic or incomplete treatment.
  • DOT decreases the chances of treatment failure and relapse.

Who can provide DOT?


  • A nurse or other trained health care worker from the patient’s county public health department normally provides DOT.
  • In some situations, it works best for clinics, home care agencies, correctional facilities, treatment centers, schools, employers, and other facilities to provide DOT, under the guidance of the local health department.
  • If resources for providing DOT are limited, priority should be given to patients most at risk.

How Do You Evaluate Persons Suspected of Having TB Disease?


1. Medical History

Clinicians should ask about the patient’s history of TB exposure, infection, or disease. It is also important to consider demographic factors (e.g., country of origin, age, ethnic or racial group, occupation) that may increase the patient’s risk for exposure to TB or to drug-resistant TB. Also, clinicians should determine whether the patient has medical conditions, especially HIV infection, that increase the risk of latent TB infection progressing to TB disease.

2. Physical Examination

A physical exam can provide valuable information about the patient’s overall condition and other factors that may affect how TB is treated, such as HIV infection or other illnesses.

3. Test for TB Infection

The Mantoux tuberculin skin test (TST) or the TB blood test can be used to test for M. tuberculosis infection. Additional tests are required to confirm TB disease. The Mantoux tuberculin skin test is performed by injecting a small amount of fluid called tuberculin into the skin in the lower part of the arm. The test is read within 48 to 72 hours by a trained health care worker, who looks for a reaction (induration) at the injection site.
The TB blood test measures the patient’s immune system reaction to M. tuberculosis.

4. Chest Radiograph

A posterior-anterior chest radiograph is used to detect chest abnormalities. Lesions may appear anywhere in the lungs and may differ in size, shape, density, and cavitation. These abnormalities may suggest TB, but cannot be used to definitively diagnose TB. However, a chest radiograph may be used to rule out the possibility of pulmonary TB in a person who has had a positive reaction to a TST or TB blood test and no symptoms of disease.

5. Diagnostic Microbiology test

The presence of acid-fast-bacilli (AFB) on a sputum smear or other specimen often indicates TB disease. Acid-fast microscopy is easy and quick, but it does not confirm a diagnosis of TB because some acid-fast-bacilli are not M. tuberculosis. Therefore, a culture is done on all initial samples to confirm the diagnosis. (However, a positive culture is not always necessary to begin or continue treatment for TB.) A positive culture for M. tuberculosis confirms the diagnosis of TB disease. Culture examinations should be completed on all specimens, regardless of AFB smear results.

6. Drug Resistance

For all patients, the initial M. tuberculosis isolate should be tested for drug resistance. It is crucial to identify drug resistance as early as possible to ensure effective treatment. Drug susceptibility patterns should be repeated for patients who do not respond adequately to treatment or who have positive culture results despite 2/3 months of therapy. Susceptibility results from laboratories should be promptly reported to the primary health care provider and the state or local TB control program.

How can a DOT provider build rapport and trust?


  • “Start where the patient is.”
  • Protect confidentiality.
  • Communicate clearly.
  • Avoid criticizing the patient’s behavior; respectfully offer helpful suggestions for change.
  • Be on time and be consistent.
    Adopt and reflect a nonjudgmental attitude.