Tensilon (edrophonium) Test

tensilon or edrophonium

How to Perform The Test 

You will need the following:

  • 1 ml of Edrophonium (Enlon or Tensilon 10mg/1ml)
  • Atopine vial (0.8mg/ml)
  • Winged infusion set (Butterfly needle)
  • 10 ml saline flush syringe
  • 1ml syringe (insulin syringe)
  • Tourniquet
  • Alcohol swab - Gauze - Paper adhesive tape

Test method:

  1. measure the distance from the upper lid margin to the lower margin of the cornea (limbus) while the patient is looking straight forward.
  2. place 1 ml of edrophonium in the 1ml syringe (insulin syringe)
  3. Apply the tourniquet to the mid-arm, clean the cubital fossa with alcohol swab.
  4. Insert the winged infusion set (butterfly needle) into the cubital vein (make sure blood starts to flow in the tail).
  5. Flush the blood with some saline and inject 0.1ml (1mg) of edrophonium and observe the eyelid for 5 seconds.
  6. Repeat step #5, injecting 0.1ml of edrophonium and waiting 5-10 seconds in-between while observing the eyelid.

Test Result: 

  • Positive response: correction of the ptosis
  • Negative response: no change in ptosis after injecting the whole 1ml.


  • Inject the edrophonium slowly, no more than 0.1ml (1 mg) at a time.
  • Keep atropine at bedside in case of hypotension or bradycardia.
  • Inform the patient about side effects that he needs to report, including palpitation, dizziness, dimming of vision.

Tensilon Test Note

Date: *****
Time: *****
Indication: Bedside test for myasthenia gravis
Resident: *********
Attending : ************

A time-out was completed verifying correct patient, procedure, site, positioning, and special equipment. The procedure was described to the patient. All the indications and potential side effects of the procedure were discussed in details (including but not limited to arrhythmia, hypotension, fainting, abdominal pain/colic..). Patient was understanding, agreeable and all questions were answered.

The Rt/Lt upper eyelid was noted at **** mm distance from the lower limbus while patient is looking straight forward.
While sitting on the exam table, a tourniquet is applied to the Rt/Lt arm. The Rt/Lt cubital fossa was cleaned with alcohol swab and a winged infusion needle was inserted into the cubital vein. 1 ml of saline was flushed followed by slow injection of edrophonium while observing the degree of ptosis.

Test result: Positive (Ptosis was corrected with edrophonium)/Negative (No response to edrophonium)

Estimated Blood Loss: 0 ml.

Complications: No complications during the procedure.

Attending Dr ***** was available for the entire procedure