Traci,
 
If your employer is not a government agency, then he/she/they cannot lawfully require you to submit to a lie detector test, and I strongly suggest that you refuse to take it. If you do sit for the polygraph, you should not be surprised if you're accused of lying and subjected to a harsh interrogation. A key purpose of the polygraph is to trick suspects into agreeing to an interrogation in the absence of legal counsel.
 
In explaining your decision to refuse the polygraph, feel free to mention this site and explain what you've learned about the unreliability of the procedure.
 
Whether you would be arrested upon failing a polygraph examination will depend on what other evidence law enforcement officials might have. Although you have nothing to hide, you are evidently considered a suspect. I think it would be very wise to get a lawyer. You need competent legal advice. Some lawyers offer a free initial consultation. The on-line Martindale lawyer locator service may be helpful in finding a lawyer in your area:
 
http://www.martindale.com
 
Also, if your employer fires you or otherwise retaliates against you for refusing the polygraph, he/she/it may be liable for damages under the Employee Polygraph Protection Act of 1988.
 
Sincerely,
 
George W. Maschke
AntiPolygraph.org

In that case, you cannot be forced to take the polygraph, and you should refuse. I wouldn't worry too much that refusing will make you look like you're hiding something. Remember, you are already a suspect, or you would not have been asked to submit to a polygraph interrogation.

Keep in mind also that the polygraph "testing" has no scientific basis and results in many truthful persons being wrongly accused of deception. It makes perfect sense for an innocent person wrongly accused to refuse the polygraph. Note that I'm not suggesting that you just skip the polygraph without saying anything. It would be prudent to call early to cancel the appointment. Again, in explaining your decision to refuse the polygraph, you may wish to refer the police (and your employer) to this website.

When I mentioned that some lawyers offer a free initial consultation I did not mean that you could get an attorney for free. The consultation is just a first (generally short) meeting or phone conversation to discuss your case.

However, in many parts of the United States and Canada there are legal aid societies that offer free legal services to those who cannot afford them. If you'd like help finding such an organization near you, please let me know, and I'll see what I can find out.

I'll need to know what city and state you live in.

Traci,

You might try contacting the Legal Services Corporation of Alabama, which has an office in Anniston:

502 AmSouth Bank Building
931 Noble Street
Anniston AL 36201

tel. (256) 237-3615
toll free (800) 884-0595

Traci,

Polygraph examiners will "test" just about anyone with an arm and a pulse. While polygraphers routinely ask subjects about any medical conditions and/or medications they may be taking, there are no scientific studies on the effects of any medical conditions on polygraphic lie detection.

Your summarization of my advice to you is correct: seek counsel, and call the detective to let him know in advance that you won't be there for the polygraph.