While writing dialogue, use action and context to avoid the dreaded use of “he said, she said.” In this scene, it is obvious who is speaking and responding.
Dr. Ashton leaned forward from behind his desk. His tortoise-rimmed glasses that made him look even more like a Turtle.
“Jane.” He paused and cleared his throat. “Your chest x-ray and sputum tests are not normal. Your right lung, well, you have–”
“The Great White Plague,” she finished his sentence. “Pithisus, Consumption, whatever you call it.”
“Yes, you have active Tuberculosis, not an inactive TB infection.”
Her husband’s blue eyes focused intently upon Aston. “I didn’t know there were two kinds of TB. What’s the difference?”
“People can have a latent TB infection without feeling sick or showing any symptoms. And at that stage, they aren’t contagious.”
Jane let out the breath she had been holding. “Well, then, I am going home.” She picked up her purse from her lap as if to leave.