DiagnoseWise
Home Articles Resources About Contact

Disease

Tuberculosis

Learn about tuberculosis, including its symptoms, diagnosis, laboratory tests, treatment and prevention.

Last Reviewed 11 Jul 2026
Reading Time 10 min read

Overview

Tuberculosis (TB) is a contagious infectious disease caused by Mycobacterium tuberculosis. It most commonly affects the lungs (pulmonary tuberculosis) but can also involve almost any organ in the body, including the lymph nodes, bones, kidneys, spine and brain (extrapulmonary tuberculosis).

The disease spreads through tiny airborne droplets released when a person with active pulmonary tuberculosis coughs, sneezes, speaks or sings. People with latent tuberculosis infection (LTBI) carry the bacteria without symptoms and cannot transmit the disease, although the infection may become active later if the immune system becomes weakened.

Despite being both preventable and curable, tuberculosis remains one of the world’s leading infectious causes of illness and death. Early diagnosis, laboratory confirmation, prompt treatment and completion of therapy are essential for reducing transmission and improving patient outcomes.

💡

Key Fact

Tuberculosis is caused by Mycobacterium tuberculosis and spreads through airborne respiratory droplets from individuals with active pulmonary disease.

Important

Tuberculosis should always be confirmed with appropriate laboratory investigations whenever possible. Delayed diagnosis or incomplete treatment increases the risk of severe disease, ongoing transmission and drug-resistant tuberculosis.

AT A GLANCE

Disease Summary

Category Infectious Disease
Cause Mycobacterium tuberculosis
Transmission Airborne respiratory droplets
Body System Respiratory System
Preventable Yes
Curable Yes

Symptoms

Common Symptoms

Most people with active pulmonary tuberculosis experience one or more of the following symptoms.

Persistent Cough

A cough lasting two weeks or longer is one of the most common symptoms of pulmonary tuberculosis. It may initially be dry before becoming productive.

Fever

Low-grade fever, particularly in the evenings, commonly occurs during active tuberculosis.

Night Sweats

Excessive sweating during sleep is a classic symptom of tuberculosis and may soak clothing or bedding.

Weight Loss

Unintentional weight loss often develops gradually due to chronic infection and reduced appetite.

Fatigue

Persistent tiredness and reduced energy are common constitutional symptoms of active tuberculosis.

Danger Signs

Seek urgent medical attention immediately if any of the following symptoms develop.

Coughing Up Blood

Coughing up blood (haemoptysis) may indicate advanced pulmonary disease and requires immediate medical evaluation.

Severe Shortness of Breath

Difficulty breathing may indicate extensive lung involvement or another serious complication.

Confusion

Confusion, drowsiness or reduced consciousness may suggest tuberculosis affecting the brain or severe systemic illness.

Persistent Chest Pain

Persistent or worsening chest pain should be evaluated promptly as it may indicate pleural disease or other complications.

Diagnosis

Clinical Assessment

Diagnosis begins with a detailed medical history and physical examination. Healthcare professionals assess symptoms, duration of illness, exposure to tuberculosis, previous infection, HIV status and other risk factors.

Physical Examination

The examination may reveal fever, weight loss, enlarged lymph nodes or abnormal breath sounds. However, physical findings alone cannot confirm tuberculosis.

Chest Imaging

Chest radiography helps identify abnormalities suggestive of pulmonary tuberculosis, including infiltrates, cavitary lesions and pleural disease. Imaging findings must always be interpreted alongside laboratory investigations.

Laboratory Confirmation

Microbiological testing remains essential for confirming tuberculosis and identifying drug resistance where appropriate.
Important
Clinical findings and imaging alone are insufficient for confirming tuberculosis. Whenever possible, diagnosis should be supported by appropriate laboratory investigations.

Laboratory Tests

Sputum Smear Microscopy

Sputum smear microscopy detects acid-fast bacilli (AFB) using Ziehl-Neelsen or auramine staining. It is inexpensive and widely available but less sensitive than molecular methods.

Sample Early morning sputum
Time Same day

GeneXpert MTB/RIF

The GeneXpert MTB/RIF assay rapidly detects Mycobacterium tuberculosis DNA and identifies rifampicin resistance, allowing earlier diagnosis and treatment decisions.

Sample Sputum
Time Approximately 2 hours

Mycobacterial Culture

Culture remains the reference standard for confirming tuberculosis and allows comprehensive drug susceptibility testing to guide treatment.

Sample Sputum or other clinical specimen
Time Several weeks

Tuberculin Skin Test (TST)

The tuberculin skin test detects immune sensitisation to tuberculosis antigens and is commonly used to identify latent tuberculosis infection, particularly in contact tracing.

Sample Intradermal injection
Time Read at 48-72 hours

Interferon-Gamma Release Assay (IGRA)

IGRAs are blood tests that detect immune responses to tuberculosis-specific antigens. They are used to diagnose latent tuberculosis infection and are not affected by prior BCG vaccination.

Sample Venous blood
Time 24-48 hours

Laboratory Note

The GeneXpert MTB/RIF assay is recommended by the WHO as the initial diagnostic test for tuberculosis in most settings due to its speed, accuracy and ability to detect rifampicin resistance.

Treatment

Standard First-Line Therapy

Standard treatment for drug-susceptible tuberculosis consists of an initial two-month intensive phase using isoniazid, rifampicin, pyrazinamide and ethambutol, followed by a four-month continuation phase using isoniazid and rifampicin. Completion of the full course is essential.

Route Oral
Duration 6 months

Treatment for Drug-Resistant Tuberculosis

Drug-resistant tuberculosis requires longer treatment with second-line agents. Newer regimens including bedaquiline and pretomanid have improved outcomes for multidrug-resistant tuberculosis.

Route Oral and/or Intravenous
Duration 6-24 months depending on resistance pattern

Treatment for Latent Tuberculosis Infection

Individuals with latent tuberculosis infection who are at high risk of progression may receive preventive therapy, such as isoniazid for six months or a shorter rifampicin-based regimen.

Route Oral
Duration 1-6 months depending on regimen

Treatment Note

Treatment must be taken consistently and completed in full. Stopping treatment early or missing doses increases the risk of treatment failure, relapse and the development of drug-resistant tuberculosis.

Prevention

BCG Vaccination

The Bacille Calmette-Guerin (BCG) vaccine is recommended for infants in high-burden countries and provides protection against severe forms of tuberculosis in children, including tuberculous meningitis.

Ensure good ventilation

Good ventilation in homes, healthcare facilities and congregate settings reduces the concentration of airborne tuberculosis bacteria and lowers the risk of transmission.

Identify and treat latent tuberculosis infection

Screening high-risk groups and treating those with latent tuberculosis infection prevents progression to active disease and reduces ongoing transmission.

Complete tuberculosis treatment

Completing the full course of treatment is one of the most important ways to prevent drug resistance and protect both the individual and the community.

Prevention Note

People living with HIV, those on immunosuppressive medications and individuals with close contact with active tuberculosis cases are at higher risk and should be prioritised for screening and preventive measures.

Risk Factors

High Risk

These individuals are most likely to develop active tuberculosis.

  • People living with HIV
  • Individuals on immunosuppressive therapy
  • People with a recent tuberculosis infection (within the past two years)

Increased Risk

These groups have a higher chance of acquiring or developing tuberculosis.

  • Healthcare workers in high-burden settings
  • Contacts of people with active pulmonary tuberculosis
  • People with diabetes, chronic kidney disease or malnutrition
  • People who use tobacco or alcohol heavily

Exposure and Social Factors

Environmental and social conditions that increase the risk of tuberculosis.

  • Living in overcrowded or poorly ventilated settings
  • Living or working in prisons, shelters or congregate facilities
  • Living in or migrating from high-burden countries

Risk Note

Tuberculosis disproportionately affects people living in poverty and in settings with limited access to healthcare. Addressing social determinants is essential for reducing the global burden of tuberculosis.

Complications

Tuberculous Meningitis

Tuberculosis affecting the brain and its surrounding membranes is a life-threatening complication that can cause severe neurological damage, disability or death if not treated promptly.

Respiratory Failure

Extensive lung disease can lead to respiratory failure, particularly in patients with delayed diagnosis or drug-resistant tuberculosis.

Drug-Resistant Tuberculosis

Incomplete or inappropriate treatment can lead to multidrug-resistant tuberculosis (MDR-TB), which is significantly more difficult and expensive to treat.

Pericarditis

Tuberculosis can infect the pericardium (the sac surrounding the heart), causing inflammation and fluid accumulation that may compromise cardiac function.

Complication Note

Early diagnosis and completion of treatment are the most effective ways to prevent serious complications of tuberculosis.

When to Seek Medical Care

Cough Lasting More Than Two Weeks

A persistent cough lasting two weeks or more, especially when accompanied by fever, night sweats or weight loss, should be evaluated for tuberculosis.

Coughing Up Blood

Any amount of blood in the sputum requires prompt medical evaluation.

Difficulty Breathing

Worsening shortness of breath may indicate significant lung involvement and requires urgent assessment.

Confusion or Neurological Symptoms

Confusion, severe headache or neck stiffness may suggest tuberculosis affecting the brain and require emergency medical care.

Emergency Advice

Anyone with known or suspected exposure to active tuberculosis should seek medical evaluation promptly, even in the absence of symptoms, as latent infection can be identified and treated before it becomes active.

Prognosis

Excellent with Early Diagnosis and Full Treatment

Most people with drug-susceptible tuberculosis recover fully when treatment is started early and completed in full.

Poorer Outcomes with Drug Resistance or Delayed Treatment

Drug-resistant tuberculosis requires longer, more complex treatment and is associated with higher rates of treatment failure and mortality.

Follow-up and Monitoring

Patients require monitoring throughout treatment to assess response, detect side effects and confirm cure at completion of therapy.

Prognosis Note

Treatment adherence is the single most important factor influencing recovery. Directly observed therapy (DOT) may be recommended to support patients in completing their full course of treatment.

Differential Diagnosis

Community-Acquired Pneumonia

Bacterial pneumonia commonly presents with cough, fever and abnormal chest imaging findings that may resemble pulmonary tuberculosis.

Lung Cancer

Lung cancer can produce similar symptoms including chronic cough, haemoptysis and weight loss, and may show overlapping radiological findings.

Non-Tuberculous Mycobacterial Infection

Infections caused by other mycobacterial species can mimic tuberculosis clinically and radiologically and require microbiological distinction for appropriate management.

Chronic Fungal Infections

Conditions such as histoplasmosis and aspergillosis may present with chronic respiratory symptoms and chest imaging changes similar to tuberculosis.

Clinical Note

Laboratory confirmation is essential because several respiratory and systemic conditions share overlapping features with tuberculosis. Clinical assessment and imaging alone are insufficient to establish the diagnosis.

References

World Health Organization (WHO)

World Health Organization guidance on tuberculosis epidemiology, diagnosis, treatment and prevention.

Centers for Disease Control and Prevention (CDC)

Clinical guidance, public health recommendations and educational resources on tuberculosis.

MSD Manual Professional Edition

Evidence-based medical reference covering tuberculosis and other infectious diseases.

Ghana Health Service , National Tuberculosis Control Programme

National tuberculosis policies, treatment guidelines and public health recommendations for Ghana.

Frequently Asked Questions

Can tuberculosis be cured?
Yes. Most cases of drug-susceptible tuberculosis can be cured with a full six-month course of first-line antibiotics when treatment is started early and completed consistently.
Is tuberculosis contagious?
Active pulmonary tuberculosis is contagious and spreads through airborne droplets. Latent tuberculosis infection is not contagious. Patients on effective treatment typically become non-infectious within a few weeks.
What is the difference between active and latent tuberculosis?
Active tuberculosis causes symptoms and can be transmitted to others. Latent tuberculosis infection means the bacteria are present in the body but are inactive, causing no symptoms and no risk of transmission. Latent infection can progress to active disease if the immune system becomes weakened.
Can tuberculosis come back after treatment?
Yes. Tuberculosis can relapse, particularly if treatment was not completed. Reinfection is also possible. Follow-up after treatment is important to monitor for any signs of recurrence.
Can tuberculosis be prevented?
Yes. BCG vaccination, good ventilation, early identification and treatment of latent infection, and completion of treatment for active disease are all effective preventive measures.