blood test

[ohpenny]

Has anyone else had this blood test carried out. Voltage gated potassium chanel? there was no explanation from the neuro as to why I had this or what they are looking for. Why are they always so vague. Also having a brain eeg. If anyone can shed some light on this I would be very grateful. Thanks and take care.x

[sllowe]

Mary -

Just wanted to say I always learn so much from your posts! I'm sure this was enlightening to not only me.

Ohpenny - hope you find out what's going on.

[ohpenny]

Thank you. You have been very helpful.

[twopack]

Did you see “Anti” before “Voltage-Gated-Potassium- Channel” or “AB” following it?  You also might see the abbreviation VGKC used (because K+ is the chemical symbol for potassium).

This test is probably just one in a pre-selected bundle of favorites this neuro has chosen to gather as much information as possible to help him determine the likely root cause(s) of whatever neurological or auto-immune symptoms you are having.

Nerves work when sodium (Na+) and potassium (K+) ions move in and out of the individual cells via special gated channels in each cell’s membrane (outer wall).  The balance inside determines the action potential - how ready it is to transmit a signal or ‘fire’.  (A similar process occurs in other types of cells where there needs to be a trigger for some other process to start.)

There are several types of potassium ion transport channels.  Those that respond to voltage changes across the cell membrane are called (logically enough) voltage-gated potassium channels.  The test you are asking about is looking for something connected with that process.

Since you chose the MS community to ask about the VGKC I’d guess your neuro may have ordered it to rule out myasthenia gravis while investigating symptoms that could be suggestive of MS.  There is another, more common test used to test for MG called the acetylcholine receptor (AChr) antibody test.  Neither test is absolutely diagnostic for MG.  It’s like that with many neurological problems.  That’s why LOTS of different tests are ordered and then evaluated with your particular history and physical exam in mind.

BUT your neuro could also be looking for something totally different.  In fact, he could be hoping some general finding in all this blood work will clarify what to investigate next.  Remember, the best person to explain why any test is ordered is the person who ordered it.  NEVER hesitate to ask your doctor questions - even when time limits are in effect.  Sometimes it’s good to preset some priorities so we can decide quickly which questions to ask immediately and which to save until later.

It sounds like your doc is doing everything possible to get the best possible look at YOU as a whole before making a diagnosis.  I do hope you get the answers you need soon.

[kwarendorf]

I don't know if I've had that test but I think Ampyra, a drug that helps with walking, is a potassium channel blocker. So there must be some relationship between MS and potassium channels.

Kyle