As part of a foot examination, your podiatrist or physician may perform a pinprick test. The test elicits pain sensation in people with diabetes and peripheral neuropathy (or patients with neuropathy in general).
The neurological test sounds uncomfortable, but it should not be painful. Pinprick testing helps the healthcare professional to understand to what extent damaged nerves have reduced or even destroyed the sensation of pain.
The pinprick test is relatively simple but must be performed carefully.
Using a pointed or sharp pin, your specialist touches various areas on your foot and applies light pressure. Usually, three dermatomes are tested, i.e., skin areas where many nerve fibers converge.
You lie on the examination table and can tell the doctor whether you feel the sensation and whether it is slightly painful. If the pin touches are noticeable and possibly even somewhat painful, your nerves are still intact and functioning. The better the diabetes is under control, the less nerve damage there usually is – and thus no or only mild neuropathy.
It is essential to understand that NO blood should flow, and the pin does not penetrate the skin. The pinprick test can be, at most, slightly unpleasant if the nerves are intact.
With damaged nerves, the sensation is even less intense. This means that the pinprick test will not cause any pain; you may feel a slight pressure. In advanced neuropathy, it is essential to take good care of the feet, protect them, and avoid wounds. Due to damaged nerves and poor blood circulation, they do not heal properly and open the door for infections. This can lead to amputations.
To know how the pinprick test should ideally feel, the specialist can first demonstrate the test on another part of your body. This will give you a direct comparison when the test is performed on your foot.
Ideally, you will not be able to see precisely where the doctor is placing the pin – pay attention to how you feel.
The specialist may also alternate between a blunt and a pointed pin to see if you feel the difference or react to the pressure applied with both variations.
A pinprick test is rarely done in isolation but is usually part of a more detailed foot examination. People with diabetes should undergo this examination regularly. Studies have shown that about 50% of older type 2 diabetics have multiple risk factors for foot ulcers.