Final answer:
To confirm primary tuberculosis, a sputum test showing the presence of Mycobacterium tuberculosis is a direct confirmation of an active infection. A positive tuberculin skin test or small areas of calcification on a chest X-ray can indicate past exposure but do not confirm active TB.
Step-by-step explanation:
To confirm a diagnosis of primary tuberculosis (TB), several tests can be used to detect the presence of Mycobacterium tuberculosis, the bacterium that causes TB. A positive tuberculin skin test, such as the Mantoux test, can indicate that a person has been exposed to TB and has developed a cellular immune response. However, a positive skin test does not necessarily confirm active TB infection, as it could be due to a previous infection or vaccination, especially with the bacillus Calmette-Guérin (BCG) vaccine. Therefore, additional evidence is needed for a definitive diagnosis.
Sputum containing TB bacilli, detected using acid-fast staining techniques like the Ziehl-Neelsen, would be a direct confirmation of the presence of TB bacteria, indicating an active infection. Small areas of calcification on a chest X-ray, known as Ghon complexes, are a sign of past infection but do not confirm active TB. Observation of hemoptysis, or coughing up blood, can be a symptom of TB but is not exclusively indicative of the disease and therefore, is not used as a diagnostic criterion for primary TB. The strongest confirmation among the given options is the presence of the TB bacilli in the sputum.