**Core Concept**
Congenital CMV infection is a significant cause of neonatal morbidity and mortality. Establishing a diagnosis in a neonate requires a combination of clinical findings, laboratory tests, and serological markers. The diagnosis is based on the detection of CMV-specific antibodies or antigens in the neonate, or the isolation of CMV from a sterile site.

**Why the Correct Answer is Right**
The correct answer is the option that does not contribute to establishing a diagnosis of congenital CMV infection. The diagnosis of congenital CMV infection is typically made using one of the following methods:

* Detection of CMV-specific IgM antibodies in the neonate's serum
* Isolation of CMV from a sterile site, such as urine, cerebrospinal fluid, or blood
* PCR detection of CMV DNA in the neonate's serum, urine, or other tissues
* Histopathological examination of tissues, such as liver or lung, showing CMV inclusion bodies

**Why Each Wrong Option is Incorrect**
**Option A:** This option might be a correct method for establishing a diagnosis, but without more information, it's unclear. However, for the sake of the question, let's assume it's a correct method.
**Option B:** This option might be a correct method for establishing a diagnosis, but without more information, it's unclear. However, for the sake of the question, let's assume it's a correct method.
**Option D:** This option might be a correct method for establishing a diagnosis, but without more information, it's unclear. However, for the sake of the question, let's assume it's a correct method.

**Clinical Pearl / High-Yield Fact**
A key point to remember is that congenital CMV infection can be asymptomatic at birth, but may cause significant morbidity later in life. This highlights the importance of screening high-risk neonates, such as those with low birth weight or preterm delivery, for CMV infection.

**Correct Answer: C.**