Apart from the above mentioned tests, various other lab tests are conducted on the patient if the results are too ambiguous to safely determine the cause of fatigue. These tests are costlier and rare to be put in use, and include chest X-ray, HIV test, electrocardiogram, echocardiogram, PPD skin testing, and serum vitamin B12. All these tests are conducted to find the occurrence of rarer diseases in the patient. They are exhaustive and costly, thus employed only when other tests fail to determine the cause of fatigue.

Urinalysis is one of the most common tests done for a disease. In this, the patient’s urine is collected in a container (minimum 3 ml). It is then subjected to a reagent test (reaction of urine with reagents to check urine’s chemical composition) and urine microscopic exam (to check for pathogens and other microscopic bodies in urine). Apart from that, color, odor, specific gravity, and pH level of urine is also taken into account. Comparing the data acquired with the data of an ideal healthy person, final cause of fatigue is determined.

Thyroid is a hormone releasing organ. The major enzymes released by it are thyroxine and triiodothyronine, and thyroid stimulating hormone (TSH) which regulates the hormone out put from the thyroid. Thyroid stimulating hormone test is used to check abnormalities in generation of any of the above compounds. Normally, TSH generation is 2-4xbaseline in 30-60 minutes, thyroxine is 4-12 ug/dl and triiodothyronine is 80-180ng/dl. If there is difference in the acquired data from the above, there is some serious problem in the thyroid that may be responsible for fatigue.

Liver function test is usually not one of the main tests for fatigue, but when fatigue comes in, there is a chance of abnormal functioning of the organ. So, in order to check the liver’s health, liver function test is conducted. In this, three markers are used for liver function and protein synthesis: serum albumin, serum bilirubin and prothrombin time. As symptoms of fatigue matches with other diseases, liver function test is one of the main tests to determine the disease. As per the result, a slight idea about the patient’s disease can be found out.

Like any load carrying fluid, blood is also vulnerable to sedimentation. In fact, sedimentation process occurs in blood vessels, though it is not significant in a healthy person. When a person is fatigued, there are high chances of undesirable blood sedimentation. In order to check this, erythrocyte sedimentation rate test is conducted. In this, the blood sample is taken from the patient, and tests are conducted on it. These tests are usually based on binding of red blood cells, increasing the sedimentation rate. The amount of sedimentation in an hour is then checked and accordingly conclusions are drawn. Remember, the blood sedimentation rate of a healthy person varies among male, female, old people, and pregnant women.

The next test that is conducted on the patient is complete blood count (CBC). In this, blood sample is taken from the patient (3 ml for adults and 1 ml for children). Any clotted specimen is rejected. This blood sample is then subjected to various blood related tests such as white blood cell count, red blood cell cunt, hemoglobin and platelet count. Usually in fatigue, red blood cells and hemoglobin is found to be in dangerously low volumes. Discrepancies in other blood tests may appear.

The first and basic test the patient should undergo is home and clinic monitoring. This test comprises of serial weights (checking weight of the body and correlating with the health data) and serial temperatures (taking body temperatures in mornings and evenings). If your weight is below the permissible weight and your body temperature is high most of the time, you require medical attention.