A 82 year old female retired farmer from Ohio with COPD presents to you with cough, weight loss, fevers and malaise. Laboratory tests reveal a mild anemia and an elevated alkaline phosphatase.
Physical examination reveals non specific rales and wheezes in the lungs.
You find calcified nodes and cavitations, predominantly in the upper lobes on chest X-ray.
Which of the following tests is most likely to be positive for Chronic Pulmonary Histoplasmosis?