A comprehensive medical checkup should allow a clinician to differentiate ME/CFS from other conditions. This involves inquiring about the patient's medical history and present disease, as well as inquiring about the symptoms to determine how frequently they occur, how severe they are, and how long they have lasted. A physical examination may reveal signs of infection, injury, or other problems not apparent from just listening to the patient talk about his or her symptoms.
Some tests may be needed to rule out other possible causes of illness. These include: blood tests to look for infections, cancer, or other diseases; urine tests to look for evidence of kidney problems or damage caused by alcohol or drugs; and tests of the brain, spinal cord, muscles, joints, and nerves. The tests used to find these problems can be invasive or simply require taking more time than is first available during an office visit. In some cases, an MRI (magnetic resonance imaging) or CT scan (computerized tomography) may need to be done instead.
Tests that show whether the body's immune system is working properly are also useful in diagnosing CFS. The two main tests used to detect immune system problems are measuring antibodies against viruses such as Epstein-Barr virus (EBV) or cytomegalovirus (CMV) and looking at certain cells of the immune system under a microscope.
A doctor or other healthcare professional commonly obtains a diagnosis, which begins with a physical examination and an investigation of the patient's history. Following that, testing and other diagnostic procedures are suggested to establish the underlying sickness or damage producing the symptoms. Testing may include laboratory studies, imaging tests, and/or biopsies.
In some cases, a diagnosis can be made based on clinical findings alone; in others, additional testing is needed. For example, if a patient comes into the office with pain in their chest, shoulder, back, or jaw, but has no past medical history indicating anything wrong with them, a doctor would first do a complete physical examination before making any assumptions about what might be causing the problem. If everything else was normal, then the doctor might suggest some basic tests, such as blood panels or x-rays, to rule out any possible underlying conditions that could cause these symptoms.
In most cases, a diagnosis is made by a physician after a comprehensive assessment of all available information. The physician may consult various reference sources, including books and journals, to obtain information about diseases that may have similar symptoms.
Diagnoses are important because they guide health professionals and patients toward appropriate treatments. It is also important to note that not all people who are diagnosed with the same illness will need the same type or amount of therapy.
Some persons with CFS/ME have a "crash," or a period of immobilizing physical and/or mental tiredness. This frequently occurs when a person is "overloaded," either physically, intellectually, or emotionally. Some CFS patients have virus-like symptoms. They are "unwell," have a fever, a sore throat, and enlarged lymph nodes. These patients need to be seen by a doctor.
Other CFS patients do not experience any "crashes." They may seem perfectly normal during the day, but when bedtime comes they are exhausted and need to sleep. Some of these people can work at night and use the morning to recuperate before starting their jobs. But most need to be supported in staying awake for long periods.
A few CFS patients experience many more "crashes" than others. They may need help from other people all the time to get through the day's activities.
People with CFS vary greatly in how severely they are affected. Some can work full time while others cannot leave their beds for days at a time. Some have many friends while others have no energy left over for anyone else. Some have very active minds while others feel mentally drained after a hard day's work. The only thing that binds us together as CFS patients is our common suffering from this invisible disease.