Last year, as part of our ongoing investigation into the troubled state of death investigation in America, PBS "Frontline," ProPublica and NPR took a closer look at what can be the most troubling and difficult cases — suspicious deaths of young children.
We discovered a growing awareness in the medical community of a variety of diseases that can mimic the symptoms of child abuse, including hereditary blood disorders, leukemia and vitamin K deficiency.
One doctor we spoke to — Dr. Michael Laposata, a pathologist and blood-clotting expert at Vanderbilt University who co-published a 2005 study on diseases that can mimic abuse — is pioneering a new blood testing regimen to rule out these types of disorders.
"If you're lucky, most places ... do the three routine tests: PT, PTT [both blood-clotting tests] and a platelet count, and that's it," Dr. Laposata told FRONTLINE in a phone interview. "It turns out most of the kids that have a bleeding problem have something other than that."
Laposata and his colleagues have devised a system to make blood testing as foolproof as possible for doctors in cases of potential abuse: They created a tiered series of blood tests, known as a "Non-Accidental Injury Coagulation Panel," which can identify underlying disorders that are more common in children. The panel can be performed with a small amount of blood, which is key when the patient is a baby.
"I think it's the most comprehensive evaluation for a bleeding disorder that anybody has put forth to date," Laposata said.
The panel is expected to be introduced soon at Vanderbilt and Dr. Laposata hopes to study its efficacy and to follow cases through the system over the years.
Because blood tests like these can only be performed on living patients whose blood is still flowing, a gap remains in diagnosing underlying conditions from autopsies. Laposata hopes that advances in genome testing could someday help close it, allowing for hereditary disorders to be better identified.
He said he also hopes his coagulation panel "will spur doctors to invent similar panels to evaluate bone injuries and skin changes that are also misdiagnosed as child abuse."
Laposata was one of a number of doctors and other experts to offer testimony during the appeals process of Ernie Lopez, a Texas man convicted in 2003 of sexually assaulting 6-month-old Isis Vas. Isis, who had bruising and bleeding in the brain and vagina, later died. Lopez was sentenced to 60 years in prison. After reviewing lab tests performed on Isis before her death, Laposata concluded that they contained "clear abnormalities" and suggested that Vas suffered from a bleeding disorder known as disseminated intravascular coagulation (DIC). He gave an affidavit in the case in 2010.
Last month, the Texas Criminal Court of Appeals voided Ernie Lopez's conviction, saying Lopez received ineffective counsel because his attorneys did not adequately challenge the prosecution's medical evidence. Potter County District Attorney Randall Sims says he will retry Lopez.
Take a look at Dr. Laposata's PowerPoint presentation highlighting the difficulty in diagnosing abuse cases. On one side is a photo of a child with bruises from a bleeding disorder; on the other, a photo of a child who was abused.
"I've been looking at patients with bleeding problems for years, more than two decades," he said. "And if you show me the two children with the bruises on their legs, I couldn't tell you that that one is the bleeding disorder. I'd have to do the blood test to find out."
Gretchen Gavett is a digital associate producer for Frontline. "The Child Cases," our film on questionable convictions in child death cases, rebroadcasts tonight on PBS (check your local listings). You can also watch it anytime online.