Context: Diagnosis of infectious disease is nearly always initiated by medical history and physical examination. More detailed identification techniques involve the culture of infectious agents isolated from a patient. Culture allows identification of infectious organisms by examining their microscopic features, by detecting the presence of substances produced by pathogens, and by directly identifying an organism by its genotype. Other techniques (such as X-rays, CAT scans, PET scans or NMR) are used to produce images of internal abnormalities resulting from the growth of an infectious agent. The images are useful in detection of, for example, a bone abscess or a spongiform encephalopathy produced by a prion.

Question: How is diagnosis of infectious disease almost always initiated?
Answer: by medical history and physical examination

Question: What does taking a culture of an infectious agent isolated from a patient allow?
Answer: detailed identification

Question: What features of an infectious organism does a culture allow examining?
Answer: microscopic features

Question: What can organisms be directly identified by?
Answer: its genotype

Question: What technique can be used to produce images of internal abnormalities?
Answer: X-rays, CAT scans, PET scans or NMR

Question: How is diagnosis of infectious disease rarely initiated?
Answer: Unanswerable

Question: What does taking a culture of an infectious agent isolated from a patient restrict?
Answer: Unanswerable

Question: What features of an infectious organism does a culture forbid examining?
Answer: Unanswerable

Question: What can organisms never be directly identified by?
Answer: Unanswerable

Question: What technique can be used to produce images of external abnormalities?
Answer: Unanswerable