When the great jazz musician Bobby Short died recently after a sudden diagnosis of leukemia, his many fans wondered: Why no warning? He reportedly entered a hospital less than a week before his death thinking that his abdominal symptoms were from diverticulitis, only to be diagnosed with leukemia. He succumbed to the disease a few days later. But diverticulitis, an infected wall of the large intestine caused by an in-pocketing of the bowel lining, is not at all similar to leukemia. So were there telltale signs of leukemia that were overlooked in the months before his death?

The answer is probably yes and no. Leukemia is a disease that can provide only vague symptoms for many months. These symptoms include fatigue, easy bruising, weakness, and nighttime fever or sweats. Anyone noticing these nonspecific symptoms should see a physician. Blood tests may suggest leukemia; an elevation in white blood count or persistent anemia warrants further investigation with a bone marrow examination.

A careful physician will pursue these abnormalities and make an earlier diagnosis than might otherwise be made. With today’s medicine, many cases of leukemia can be cured or at least controlled. But if Short had any of these symptoms, he may have dismissed them as not significant enough to merit a visit to the doctor until they became too severe to ignore.

Leukemia isn’t the only disease that often comes in below the body’s radar. Many diseases have mild symptoms to begin with that could mean something worse. This is why a person who is feeling a bit “out of sorts” for a while should contact his or her physician.

Fatigue can be a symptom for a variety of underlying conditions, including hypothyroidism (especially in women), Lyme disease, and depression. Screening for these problems in a clinic or doctor’s office is a crucial part of health care. All three conditions can be treated and cured with medications.

Nighttime fevers or sweats can be a sign of infection, most commonly viral or bacterial, and less commonly the atypical mycobacteria, tuberculosis. Persistent sweats or cyclical fevers would cause a doctor to consider an occult cancer, where a growing malignancy is still too small to manifest more overt symptoms. Occult cancers include lymphoma and leukemia.

An experienced physician does not always expect the symptoms to add up to a certain illness. Each symptom or finding on examination has its own response protocol, usually requiring the ordering of a pre-considered series of tests. The doctor looks smart when the test reveals a condition that he or she may have been suspecting, but whether or not this occurs, all bases are covered.

Patients shouldn’t think that a test to rule out a serious condition means that the news is bound to be sinister. In fact, the majority of the time, a test is ordered to rule out, rather than rule in, a problem. Better not to miss something serious than to test for something that turns out to be normal. A heart attack, for example, occurs less than a hundredth of the time that a person with chest pain comes to an emergency room. But it is so important to the health of the patient not to miss a heart attack that the blood test to distinguish it should be performed on all chest pain patients coming into the ER.

In Short’s case, earlier diagnosis might have led to a more readily treated disease. Leukemia is one of many diseases that respond better to treatment if caught early.

Recently, I saw a patient with a slight cough and a low-grade fever. She was only 25 years old, and I suspected that she had a mild viral infection. But when she took a deep breath, she complained of very slight chest discomfort. I decided to perform a chest X-ray as a precaution, expecting it to be normal, as so many others under similar circumstances had been. To my surprise, I discovered a snowball-white patch of pneumonia in the left lung. She narrowly avoided hospitalization because she was so young, and she responded well to antibiotics. Weeks later she was cured, and the follow-up X-ray was completely clear.

Now each time this patient has the slightest cough she worries about pneumonia. I may never find it again, but we both, doctor and patient, are wise to be cautious.