Doctors aren’t perfect. Even with all their studying, training and experience – there are times when mistakes are made. Illnesses and issues can have common symptoms which medical professionals can misdiagnose, sometimes to the patient’s detriment.

Sepsis kills 250000 Americans each year according to the CDC. “Sepsis is, unfortunately, common. When you look at the numbers, it’s the third most common death in the United States,” Dr. Greg Martin, a critical-care physician at Emory University School of Medicine in Atlanta, told ABC News.

The doctor called sepsis “the great masquerader” and said it’s easy for doctors to mistake it for the flu.

The doctor continued: “There’s not a single test for sepsis. And if it’s not treated quickly, it can often be fatal.”

On December 17th, 12-year-old Alyssa Alcaraz died at Kaweah Delta Medical Center in Visalia, California. The lively girl was known for her love of singing and making her family laugh. Just three days before her death, Alyssa was diagnosed and treated for the flu.

Alyssa’s mother, Keila said her daughter was sent home with ibuprofen and instructions to rest for a week to ten days:”For her, it wasn’t even [the flu]. It was just three days, and she was dead,” the mother told ABC News.

Alyssa’s death certificate says she died of cardiac arrest and septic shock. Septic shock is the body’s response to infection. Sepsis can ‘rapidly cause tissue damage, organ failure, and death.’

Alyssa’s mother has no intentions to sue the hospital. She wants doctors nationwide to develop tests to give those exhibiting similar symptoms to prevent these tragedies from happening further: “I have mixed emotions. I know doctors and clinics are so overwhelmed with flu cases right now. My thing is, yeah, I could point fingers, but as a mother, I missed it, too,” she said.

Dru Quesnoy, a spokeswoman for the hospital, declined to discuss Alyssa’s case, saying, “Patient privacy laws prohibit us from commenting on the story.”

Before becoming ill, Alyssa was your average healthy junior high student. Ten days before her death, she participated in a choral concert at school: “I have four kids, three girls, and a boy, and she was my second,” Alcaraz said. “She was the clown of the family. She loved music. She loved singing. She loved science at school.”

If sepsis is so common, how do we get it? The CDC says: “Sepsis happens when an infection you already have -– in your skin, lungs, urinary tract or somewhere else -– triggers a chain reaction throughout your body.”

What’s the difference between an infection and sepsis? “An infection occurs when germs enter a person’s body and multiply, causing illness, organ and tissue damage, or disease. If that infection isn’t stopped, it can cause sepsis.”

There are four kinds of infections that are linked to sepsis: lungs (pneumonia), kidney ( urinary tract infection ), skin and gut. The tricky thing is, there is no one typical symptom to alert doctors that a patient is septic. Some symptoms can include: “combination of confusion or disorientation, shortness of breath, high heart rate, fever or shivering or feeling very cold, extreme pain or discomfort, and clammy or sweaty skin.”

Those with sepsis are treated in the hospital. Rapid response is the best response. Giving the patient antibiotics, maintaining blood flow to the major organs and perhaps most importantly, treating the source of the infection can save lives.

Perhaps Alyssa’s life could’ve been spared if she’d received a more accurate diagnosis. The flu has bombarded California and 45 other states. It’s not difficult to see how she could be misdiagnosed. But how devastated her family must be with her loss.