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Laboratory Diagnosis of TOS2019-01-29T22:26:46+00:00

Laboratory Diagnosis of TOS

For many medical conditions, patients expect to give blood or undergo laboratory tests. Unfortunately, for TOS patients, there is no significant lab test that helps doctors make the diagnosis. However, doctors have tried over the years to find such lab tests. Read an introduction to the lab tests for TOS patients.

Laboratory tests for neurogenic TOS

Laboratory tests for venous TOS

Lab tests for neurogenic TOS

There is a single laboratory test that doctors have used in patients with neurogenic TOS on a regular basis. By itself, the test possesses little importance. It has poor sensitivity and specificity and provides little anatomic information. The test does not significantly alter treatment decisions for most doctors. However, this test formed the basis for a firestorm of controversy in the TOS community several decades ago. Echoes of this controversy reverberate today.

Laboratory tests for venous TOS

A few articles in the medical literature have suggested that patients with venous TOS have blood that forms clots more easily. For this reason, some doctors will perform blood tests on patients with venous TOS. The blood tests measure how fast the patient’s blood will form clots. If this test is abnormal, further tests can measure the levels of specific clotting factors in the blood.

Unfortunately, only a minority of patients with venous TOS will have positive results on these tests. In other words, many patients develop venous TOS with normal blood clotting. Thus, the blood tests do not improve diagnosis in these patients. Clinical signs and imaging tests are much more valuable to these patients and their doctors.

Diagnosis of TOS

What diagnostic tests are useful in TOS?

What tests help to diagnose TOS?

Arterial TOS and venous TOS patients usually present in dramatic fashion. Clinical examination and diagnostic tests in these patients are typically straightforward. However, these two types of TOS are rare.

Patients develop neurogenic TOS much more commonly. And, unfortunately, the diagnosis of neurogenic TOS is much more challenging than the diagnosis of arterial or venous TOS. Once your doctor suspects you have neurogenic TOS, he or she may perform a specialized physical examination. But these tests are known to be poorly accurate.

Modern imaging tests provide an amazing amount of detailed data showing the anatomy of the thoracic outlet. And in patients with neurogenic TOS, good imaging studies show exactly what is compression the nerves, arteries and veins. This information allows better treatment decisions, including whether to go to surgery, and what type of surgery is best.