Recently, a teenager came into our emergency department at St. Christopher's Hospital for Children with vague symptoms of fatigue, abdominal pain, and pinkeye. He had been seen several times by his primary-care doctor and had made two emergency room visits over the last few months with similar vague symptoms.

He was never offered an inexpensive, rapid, potentially lifesaving test the government has recommended for the last six years until he came to our ER.

By then, his body was so ravaged by an undiagnosed infection that his immune system was completely compromised. His HIV test was positive. His viral load was in the millions and his CD4 count - measuring cells that help fight certain infections - was undetectable. He had AIDS.

Sadly, his story is repeated hundreds of times daily across the nation, all unnecessarily.

HIV/AIDS is the seventh leading cause of death in the United States among people age 15 to 24, and half of young people infected with HIV are not aware of it.

An unbelievable 26 percent of all new HIV infections are among those 13 to 24.

One thousand teenagers and young adults are infected monthly at a cost of $400,000 per person over a lifetime of care that, if started later in the disease, becomes more ineffective and costly.

In Philadelphia, the incidence of HIV is five times the national rate, and it's easy to see why. Among Philly high school teenagers, 63.5 percent have had sexual intercourse, and an astonishing 14.5 percent had their first sexual encounter before age 13.

One quarter have had more than four sexual partners, and 11.1 percent drank alcohol or used drugs before their latest sexual encounter.

By 2006, 60,000 new HIV cases were being diagnosed yearly in the United States and there had been no improvement since the mid-1990s. So on Sept. 22 that year, the Centers for Disease Control and Prevention recommended screening everyone age 13 to 64 in all health-care settings.

How are we doing?

A recent study in JAMA Pediatrics showed that only 22.6 percent of high school students nationally had been tested for HIV.

What to do?

Test.

Test in all health-care settings. Health-care providers should follow the CDC recommendations. Parents and guardians of teenagers should ask their providers to discuss HIV and testing, even with teens who are not sexually active (statistics tell us we don't always know).

At St. Chris, we still provide opt-out HIV testing to all patients 13 and over. But we've undergone a culture change and transitioned from risk-based to routine (regardless of risk) testing, making HIV testing a standard of care for our patients. Here's why we changed our policies.

In 2011, nearly 800 people were newly diagnosed with HIV in Philadelphia; almost 40 percent were in the 13-29 age range.

Community groups like CHOICE, ActionAIDS, and Y-HEP have set the standard for teaching the importance of prevention, testing, and treatment.

Many of these programs are on the www.cap4kids.org/philadelphia website, which can help teens find resources in their communities.

Our goal is to help those like the teen diagnosed with AIDS in our ER learn their status sooner and enable others never to hear the words, "Your test is positive."

Daniel Taylor is an associate professor at Drexel University College of Medicine and a pediatrician with St. Christopher's Hospital for Children. His e-mail address is Daniel.Taylor@DrexelMed.edu.