Hello and welcome to HCM,
You have mentioned that your child is suffering from fever
since few days.
Your doctor is suspecting respiratory infection.
Pyogenic infections or bacterial infections are common cause of respiratory tract
Bacterial infections cause a condition called pneumonia
A X-ray of the chest can detect consolidation/ pneumonia.
Another cause of fever and respiratory symptoms is TB.
TB is screened by Mantoux test
In this test PPD is injected into the skin and the reaction is seen at an interval of 48-72 hours.
Negative Mantoux test does not rule out TB.
Most sensitive test for TB is culture of the sputum (TB involving lungs).
If you have more queries, i will be glad to answer.
Dr Shailja P Wahal