An anion gap is not a lab test, but rather a calculation made using the results of an electrolyte panel, explains Lab Tests Online. As of February 2015, the fair price for an electrolyte panel is $36 at direct-to-consumer laboratories and $18 at physician offices, according to the Healthcare Blue Book. These prices can vary however, based on facility type and geographic location.
How much people pay for laboratory tests also varies based on insurance coverage. A patient can save money by asking for price quotes from several laboratories and having tests performed at the lab charging the lowest prices. Although an electrolyte panel typically costs less at a physician's office, there might be an additional fee for an office visit, making a direct-to-consumer laboratory the less expensive option.