Eric Dane was initially misdiagnosed with a treatable illness months before receiving his ALS “death sentence,” his posthumous memoir reveals.

In “My Book of Days: A Memoir in Moments,” out Tuesday, the actor wrote that he sought answers while “gradually losing any use of [his] right hand.”

He recalled, “First, I saw a hand specialist, who passed me off to another hand specialist, who sent me to a neurologist.”

While the neurologist speculated Dane “had contracted some form of neuropathy,” he felt the “Grey’s Anatomy” alum’s struggles were “above [his] pay grade” and sent him to another doctor.

“I shuttled from doctor to doctor and underwent a battery of tests, including one called an EMG, an electromyography test,” Dane remembered, noting that he eventually received “a diagnostic consensus” of multifocal motor neuropathy.

He described the condition as “a rare autoimmune disorder causing extreme muscle weakness” with “90 percent effective” treatment.

However, Dane did not respond to the treatment — which left his medical team “scared.”

His primary care doctor subsequently gave Dane “grim” news, saying, “We’ve been discussing ALS. But we have to wait and see.”

The “frustrated and fed up” “Euphoria” alum went on to undergo a lumbar puncture, spinal fluid extraction and brain scans.

Dane was diagnosed nine months later in 2024, and he called the disease a “death sentence” and the makings of a “horror movie” in his book.

He went public with his ALS battle in April of the following year.

Dane died in February at 53 and is survived by daughters Billie, 16, and Georgia, 14, whom he welcomed with then-wife Rebecca Gayheart.

Dane called Gayheart, whom he split from in 2017 after more than a decade of marriage, after his diagnosis, recounting the conversation in his tell-all.

After telling his estranged wife the diagnosis was “what [they’d] feared,” he felt “a violent impact, like getting the wind knocked out of” him.

He experienced “body-shudder[ing]” sobs while Gayheart “wail[ed]” over the phone.

Last month, Gayheart told People about the emotional moment, calling Dane’s words a “punch to the gut.”

She told the outlet that if she could talk to her ex now, she would tell him, “I’m going to look after [our] girls and protect them with everything in my body and soul.”