We may be concerned either with the fact, or with the type. Is anemia present? If so, what kind?
The question whether or not anemia is present can be decided only and sufficiently by testing the hemoglobin. We should never assume that anemia is present either from the symptoms alone, or from the appearance of the patient, or from both taken together. Mistakes from this cause are many. On the other hand, there can be no mistake in supposing that the patient who has a low hemoglobin is anemic, and practically no mistake in supposing that the patient whose hemoglobin is normal, or nearly so, is not anemic.
Diagnoses of anemia are very much more frequent than the facts justify. Patients are frequently treated for anemia when nothing more than a pale skin substantiates the diagnosis. The treatment does no harm except in so far as it may prevent us
CABOT RC. THE DIAGNOSIS OF ANEMIA.. JAMA. 1907;XLIX(8):636-639. doi:10.1001/jama.1907.25320080004001a