What are the next steps after a positive Tuberculosis (TB) test?

From the Guidelines

If you have a positive TB test, you should see a healthcare provider immediately for further evaluation to determine if you have active tuberculosis disease or latent TB infection. This typically involves a chest X-ray and possibly sputum tests.

• For latent TB, treatment usually involves taking isoniazid (INH) 300mg daily for 6-9 months, or a shorter regimen like isoniazid plus rifapentine weekly for 12 weeks 1.
• For active TB disease, you'll need a combination of medications typically including isoniazid, rifampin, ethambutol, and pyrazinamide for 2 months, followed by isoniazid and rifampin for 4 more months 1. During treatment, regular follow-up appointments are essential to monitor for side effects and ensure the infection is responding.
• It's crucial to complete the full course of medication even if you start feeling better, as incomplete treatment can lead to drug-resistant TB 1.
• While on treatment for active TB, you may need to temporarily isolate to prevent spreading the infection to others, especially during the first few weeks when you're most contagious. Additionally, patients with HIV infection should be treated for latent TB infection, and options include isoniazid daily or twice weekly for 9 months, or 4 months of therapy daily with either rifampin or rifabutin 1.

From the FDA Drug Label

Isoniazid is recommended for all forms of tuberculosis in which organisms are susceptible. However, active tuberculosis must be treated with multiple concomitant antituberculosis medications to prevent the emergence of drug resistance. Isoniazid is recommended as preventive therapy for the following groups, regardless of age. Candidates for preventive therapy who have HIV infection should have a minimum of 12 months of therapy. Persons with abnormal chest radiographs that show fibrotic lesions likely to represent old healed tuberculosis (≥ 5 mm). Candidates for preventive therapy who have fibrotic pulmonary lesions consistent with healed tuberculosis or who have pulmonary silicosis should have 12 months of isoniazid or 4 months of isoniazid and rifampin, concomitantly.

The next steps for a positive TB test are:

• Confirmatory testing: to determine if the patient has active or latent tuberculosis
• Risk assessment: to identify individuals at high risk of developing active tuberculosis, such as those with HIV infection, abnormal chest radiographs, or other medical conditions that increase the risk of tuberculosis
• Preventive therapy: with isoniazid for at least 12 months for certain high-risk groups, or 4 months of isoniazid and rifampin concomitantly for those with fibrotic pulmonary lesions consistent with healed tuberculosis or pulmonary silicosis 2
• Multidrug regimen: for active tuberculosis, consisting of rifampin, isoniazid, and pyrazinamide, with the possible addition of a fourth drug, such as streptomycin or ethambutol, depending on the risk of resistance and the patient's condition 3

From the Research

Next Steps After a Positive TB Test

• A positive TB test indicates that a person has been infected with Mycobacterium tuberculosis, but it does not necessarily mean they have active tuberculosis 4.
• The standard treatment for latent tuberculosis is nine months of isoniazid taken daily, or twice weekly under direct observation by a healthcare worker 4.
• Initial therapy for patients with active or suspected tuberculosis should include isoniazid, rifampin, pyrazinamide, and ethambutol until susceptibility is known 4.
• Treatment must include at least 4 drugs to which the organism is susceptible; the duration of therapy should usually be 18-24 months for confirmed multidrug-resistant tuberculosis or extensively drug-resistant tuberculosis 4.

Treatment Options

• Isoniazid alone is adequate for prophylaxis 5.
• Triple-drug therapy may be indicated initially for cavitary pulmonary disease, meningitis, miliary disease, and moderate to severe renal disease 5.
• Short-course therapy twice or three times weekly with isoniazid and rifampin may be used in cavitary pulmonary disease and probably in these other serious infections as well 5.
• A regimen of isoniazid, rifampin, pyrazinamide, and ethambutol given daily for 6 months produced successful outcomes when used in a public health tuberculosis clinic as routine therapy for isoniazid-resistant tuberculosis 6.

Important Considerations

• The major cause of therapeutic failure is noncompliance of the patient in taking the medication regularly 5.
• The second major cause of treatment failure is resistance of tubercle bacilli to the antimicrobial agents used 5.
• Directly observed therapy by a healthcare worker should be offered to all patients with active tuberculosis to minimize treatment failure, relapse, and the emergence of drug resistance 4.
• Drug-drug interactions can occur with first-line anti-tuberculosis drugs, and significant interactions were observed in case of the drug mixtures 7.