"CBS This Morning" has partnered with Kaiser Health News and NPR on their "Bill of the Month" series, which uncovers shocking medical bills. This week, we explore the story of woman who got a bill for more than $28,000 after a routine trip to the doctor.

A woman in New York City went to her doctor because of a sore throat. Then days later, she got a medical bill for more than $28,000.

Alexa Kasdan, who is insured by Blue Cross and Blue Shield of Minnesota, wanted to be sure her cold symptoms weren't anything serious, so she made an appointment with a doctor she had seen before, Dr. Roya Fathollahi, reports CBS News correspondent David Begnaud.

"I thought maybe because my throat had started hurting a lot, I potentially had strep throat," Kasdan said.

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Her doctor gave her a step throat culture. "She sent in a nurse, and they did blood work. That was it. She gave me a prescription for antibiotics. I left," Kasdan said.

Within 10 days, Kasdan felt better, but then she got several unexpected messages from the doctor's office. While both the doctor and the lab that performed the blood tests were in Kasdan's insurance network, the lab that processed the throat swab was not. Kasdan learned that the doctor had ordered an extensive, and expensive, array of respiratory tests.

"She didn't give me any indication that she was going to do anything more than just a basic strep test," Kasdan said.

The bill for those throat swab tests totaled more than $28,000. After deducting a co-pay, the insurance company paid the claim, sending Kasdan a check for $25,865.

Kasdan said her doctor's office, which shares a phone number and address with the lab, wanted her to turn over that entire insurance payment immediately.

"Blue Cross Blue Shield also kind of dropped the ball here, and they should have flagged this and they didn't," Kasdan said.

Kasdan gave the check to the doctor, but Blue Cross Blue Shield told Kaiser Health News it is now reviewing the claim and has placed a hold on the check. Kasdan's doctor did not respond to requests for comment.