Every so often, a news story will circulate about a snakebite victim getting another shock: a hospital bill charging them tens to hundreds of thousands of dollars. But while antivenom isn’t exactly cheap and easy to make, the price tag that comes along with these life-saving doses has raised eyebrows among even the researchers who make the stuff.

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Getting bitten by a snake isn’t that uncommon – according to the Centers for Disease Control, about 7,000 to 8,000 people are treated for snakebite every year in the United States alone. Doctors Without Borders also reports that as many as 100,000 people around the world die from snakebite every year. But even Leslie Boyer, founding director of the University of Arizona’s VIPER Institute, was shocked that hospitals can pay up to $2,300 for a single vial of antivenom, Christopher Ingraham writes for The Washington Post.

The process of making antivenom is complicated. In order to make some of the most common rattlesnake antivenin, sheep have to be injected with the snake’s venom and then have their antibodies harvested by doctors. But after reading another of Ingraham’s articles from earlier this summer that analyzed the high cost of antivenom treatment, Boyer realized she didn’t know why the antivenin made in her own labs was so prohibitively expensive.

“Physicians are counseled to steer clear of involvement in the pricing of the drugs we study, for good reason: financial conflict of interest by care providers imperils our ability to provide objective patient care,” Boyer wrote in an article that will be published in an upcoming issue of The American Journal of Medicine. “We were crestfallen to discover...that the chosen wholesale price for this otherwise excellent drug was set too high to be cost effective, even in the treatment of critically ill children...Somehow, a US drug whose sister product retailed in Mexico at $100 was resulting in bills to Arizona patients of between $7,900 and $39,652 per vial.”

After examining cost data from every step of the process, from the factory floor to hospital billings, Boyer developed a pricing model that shows how much each part contributed to the ultimate expense. Fees and costs for licensing, regulation and hospital profits amounted to 27.7 percent of the overall cost and clinical trials made up just 2.1 percent. The cost of making the antivenom, including research, development, animal care and plasma harvesting? A mere 0.1 percent. As for the remaining 70.1 percent, Boyer found that the cost was due to hospital markups used in negotiations with insurance companies, Ingraham writes.

Depending on your insurer and hospital, prices for medicines from antivenom to Advil can fluctuate dramatically thanks to inconsistent pricing. That’s why a person in North Carolina might pay about $5,400 for antivenom treatment while another in Arizona might only pay about $347, even if they have the same insurance company. And if that person is unlucky enough to be uninsured, they could be charged up to hundreds of thousands of dollars, Tom Marcinko reports for Al-Jazeera America.

The high cost of antivenom isn’t the only problem with the treatment: because relatively few people need the treatment compared to some other illnesses, pharmaceutical companies tend to put antivenom on the back burner. Now, Doctors Without Borders is warning that stockpiles of a critical antivenom used to treat deadly bites from 10 different African snakes are about to run out because it isn’t profitable enough for the company that makes it. While the company has offered to give the recipe for the antivenom to another company, no plans have been set yet. In the meantime, the last of the antivenom will expire within the next year, Michaleen Doucleff reports for NPR.

With that in mind, it might be best to skip snapping a selfie with a rattlesnake unless you’re a millionaire.