When you're struggling to sleep, many factors could be at play. You may be drinking too much caffeine or staying up too late. Or perhaps you have a medical condition that is causing fatigue.
To find out the cause of your sleep problems, your doctor may do a number of tests. These may confirm or rule out various health conditions and other problems.
Hematocrit and hemoglobin test
Your doctor may order a hematocrit/hemoglobin blood test to measure the levels of these substances in your blood. If you have low hematocrit and/or hemoglobin, you may have anemia. This is a blood disorder that can cause you to be tired and sleepy during the day. It can also lead to restless legs syndrome. Abnormal levels of may also mean you have an iron deficiency, chronic illness, or lung disease. All of these can contribute to sleep problems.
Arterial blood gases test
An arterial blood gas test measures the levels of gases, including oxygen, in the blood. The test is done by drawing blood from an artery in the wrist. This takes only takes a few minutes. The test can diagnose or rule out a variety of conditions, including problems with breathing. Difficulty breathing, shortness of breath, and sleep apnea are breathing issues that can affect sleep.
Thyroid function test
Thyroid function can be looked at by checking the levels of thyroid hormones TSH, T3, and T4 in the blood. These hormones help regulate the body's metabolic processes. A thyroid function test may signal an underactive thyroid gland. This is called hypothyroidism and it may cause fatigue and lethargy. Or it may show an overactive thyroid, a condition called hyperthyroidism. This can cause insomnia. Either of these conditions can play a part in sleep difficulties.
Drug and alcohol toxicology screening
A test to check for drugs and/or alcohol in the blood can help determine whether drugs or alcohol are the cause of sleep disorders, such as insomnia. People may use drugs or alcohol as sleep aids but doing so can backfire. For example, a glass of wine before bed can lead to drowsiness, so falling asleep is easy. But the alcohol can then cause middle-of-the-night wakefulness, resulting in insufficient sleep. You may give a blood or urine sample in either a doctor's office or a lab.
Epworth sleepiness score
This test is a questionnaire that helps gauge how sleepy you are during the day. It also looks at how likely you are to fall asleep during daytime hours and during certain activities, such as watching TV or sitting in a car. Chronic daytime sleepiness may mean that you have a sleep disorder.
Beck depression index
This test is a questionnaire to help spot signs of depression. The test involves asking questions about feelings of sadness, guilt, self-criticism, fatigue, sleep problems, and other symptoms that often signal depression. Depression and some of the medicine used to treat it are commonly linked to insomnia and other sleep disorders.
In sleep medicine, the electrooculogram or EOG is used to detect different types of eye movements during sleep. Electrodes that measure electrical signals based on eye movements are placed on the sides of the eyes. These allow the doctor to identify different stages of sleep, particularly rapid eye movement or REM sleep. It is used as part of the polysomnogram.
Chin and leg electromyogram
The electromyogram test, or EMG, measures the electrical activity of the nerves in the chin and the legs. It's often done in a sleep clinic during a sleep study. It involves attaching electrodes to the skin on the legs and/or chin to look at the activity of the muscles. The recorded nerve activity can show patterns of sleep and wake cycles, which can help diagnose sleep disorders.
A polysomnography test may be done to check the patterns of brain waves and other physical functions during sleep. The test is often done in a sleep clinic over the course of a night to look at the body's activity during sleep. The test measures heart rate, respiration, muscle activity, blood pressure, brain activity, and eye movement. The test can indicate whether you are asleep and whether you have any abnormalities in the sleep pattern.