Brief Answer:
See below detail answer
Detailed Answer:
If there is a H/O
Pneumonia, 4 years ago, most probably,
granuloma has formed as a healing process after Pneumonia. Granuloma also can form after some yeast infection. There could be several other uncommon reasons for this Non calcified Granuloma, and there are number of tests, which can be done in a logical way determined by patient's high risk factors, symptoms, H/O smoking, size of nodules, change is size on interval X Rays etc.
Calcified granuloma just confirms an Old infection and rule out Cancer. Non-calcified could be anything.
Most definitive test would be Lung
Biopsy or low dose
CT Scan of Lungs, specially to rule out any possibility of Cancer.
Possibility of TB can be ruled out by Tuberculin skin test,
ESR, Sputum test for AFB etc, though It is not always possible to diagnose
Tuberculosis by above test and we have to use our clinical acumen.
If your wife has any other high risk factor, your doctor would have definitely advise her to go for further test, but it is good to be informative and to be proactive.
If you have further question, you may ask with more description, X ary reports, or size of the nodule, age of your wife, occupational history, H/o exposure of active or
passive smoking etc.