Over the last couple of years, the big news in autism is that autism presents differently in girls than in boys. This is why it goes undetected in girls far longer, and why it takes longer for girls to be diagnosed with autism.
Additionally, autism research has shown that girls with the same genetic mutations as boys diagnosed with autism don’t always develop autism. Understanding the role gender plays in autism will prove beneficial in treating autism in both males and females.
While there is no blood test to confirm or rule out autism, there are a number of factors considered. Read more via this link.