NAS Score, Baby Withdrawal, Finnegan Chart, NASH/NAFLD Liver Biopsy, Scoring Guide

NAS Score:

• What is NAS Score?
• NAS Score in Baby Withdrawal (Neonatal Abstinence Syndrome)
• NAS Score Finnegan Chart
• NAS Score in NASH/NAFLD Liver Biopsy
• NAS Score Scoring Guide

What is NAS Score?

The term NAS Score can refer to two different medical contexts: neonatal abstinence syndrome (NAS) in infants and the NAFLD activity score (NAS) used in liver biopsies. Both systems use scoring methods to measure disease severity and guide treatment decisions. In neonatal medicine, the NAS score evaluates withdrawal symptoms in newborns exposed to drugs in utero. In hepatology, the NAFLD activity score evaluates inflammation and fat buildup in the liver.

Despite sharing the acronym, these scoring systems are entirely different in purpose. The neonatal NAS score is more clinical and symptom-focused, while the NAFLD activity score is histological, based on biopsy results. Both help standardize assessment and improve patient care. Understanding the context in which the term is used is essential for healthcare providers and patients alike.

NAS Score in Baby Withdrawal (Neonatal Abstinence Syndrome)

In pediatrics, NAS Score refers to the evaluation of newborns experiencing withdrawal symptoms due to maternal drug exposure during pregnancy. These symptoms may include tremors, irritability, feeding difficulties, vomiting, and excessive crying. The NAS scoring system helps clinicians determine the severity of withdrawal and whether pharmacological treatment is necessary.

Regular scoring every few hours provides a clear picture of the infant’s progress and ensures timely medical intervention. Infants with higher NAS scores are often treated with medications such as morphine or methadone, alongside supportive care. This scoring system has become a cornerstone in neonatal intensive care units for managing opioid-exposed newborns.

NAS Score Finnegan Chart

The Finnegan Neonatal Abstinence Scoring System (FNASS) is the most widely used tool to calculate NAS scores in newborns. It consists of a detailed chart listing more than 20 clinical signs of withdrawal, such as high-pitched crying, sleep disturbances, sneezing, yawning, diarrhea, and poor feeding. Each symptom is assigned a numerical value depending on severity.

NAS Score Finnegan Chart:

Finnegan Neonatal Abstinence Scoring — Items & Points

Domain	Sign	Criteria	Score
CNS / Neurologic	High-pitched cry	Intermittent / consolable	2
	High-pitched cry	Continuous / inconsolable	3
	Sleep after feed	Sleeps < 3 h	1
	Sleep after feed	Sleeps < 2 h	2
	Sleep after feed	Sleeps < 1 h	3
	Moro reflex	Hyperactive	2
	Moro reflex	Markedly hyperactive	3
	Tremors	Mild, disturbed only	1
	Tremors	Mild, undisturbed	2
	Tremors	Moderate–severe, disturbed	3
	Tremors	Moderate–severe, undisturbed	4
CNS (cont.)	Increased muscle tone	Hypertonia	2
	Excoriations	Skin excoriated (e.g., knees, face)	1
	Myoclonic jerks	Present	3
	Generalized seizures	Any seizure activity	5
	Metabolic / Vasomotor / Respiratory	Sweating	Present	1
Fever		37.3–38.3 °C (99.1–100.9 °F)	1
Fever		≥ 38.4 °C (≥ 101.1 °F)	2
Frequent yawning		≥ 3 per scoring interval	1
Mottling		Cutis marmorata	1
Nasal stuffiness		Present	1
Sneezing		≥ 3 per scoring interval	1
Nasal flaring		Present	2
Respiratory rate		> 60/min without retractions	1
Respiratory distress		> 60/min with retractions	2
Gastrointestinal	Excessive sucking	Hyperphagia / frantic	1
	Poor feeding	Uncoordinated / weak suck	2
	Regurgitation	Vomits after feeds	2
	Projectile vomiting	Forceful emesis	3
	Stools	Loose	2
	Stools	Watery	3

How to Use:

• Score the infant every 3–4 hours, ideally just before a feed.
• Assign points for each sign observed during the interval; add to get a total NAS score.
• Common treatment triggers: ≥ 8 on two consecutive scores or ≥ 12 once (follow your local protocol).
• Use in conjunction with non-pharmacologic care (swaddling, low-stimulus environment, frequent feeds).
• Document timing, feeding tolerance, and consolability along with the score.

Notes & Safety:

• Hospitals may use a modified Finnegan or EAST/Eat-Sleep-Console pathways—always follow institutional guidelines.
• Consider other causes of irritability, fever, or poor feeding (infection, hypoglycemia, electrolyte imbalance) in your differential.
• Use standardized training and inter-rater checks to improve scoring reliability.

Scores are recorded at regular intervals, typically every 2 to 4 hours. A total score above a certain threshold (commonly 8 or higher) often indicates the need for medical treatment. The Finnegan chart helps ensure standardized evaluation across different caregivers, reducing subjectivity and improving patient outcomes. Variations of this tool, such as the modified Finnegan score, are also widely used in neonatal units.

NAS Score in NASH/NAFLD Liver Biopsy

In hepatology, NAS Score stands for NAFLD Activity Score, which is used to evaluate the severity of non-alcoholic fatty liver disease (NAFLD) and non-alcoholic steatohepatitis (NASH). It is calculated during liver biopsy by assessing three key features: steatosis (fat accumulation), lobular inflammation, and hepatocellular ballooning. Fibrosis is reported separately.

The score ranges from 0 to 8, with higher scores indicating more severe liver injury. A score of 5 or more is considered diagnostic of definite NASH, while lower scores suggest mild or borderline disease. This system provides a standardized framework for clinical trials and patient monitoring, though it is not used alone for diagnosis without clinical correlation. The NAS score helps track disease progression and response to treatment in patients with fatty liver disorders.

NAS Score Scoring Guide

The scoring guide for NAS differs between neonatal withdrawal and liver biopsy assessment. For baby withdrawal (Finnegan score), each symptom is rated on a chart, and the total guides whether medication is required. For liver biopsies, pathologists use a structured grading system for steatosis (0–3), lobular inflammation (0–3), and ballooning (0–2), which are summed to form the NAS score (0–8).

Healthcare providers must always interpret NAS scores in the proper context. For neonates, it ensures withdrawal symptoms are managed compassionately and consistently. For liver disease, it provides a quantitative measure of disease activity and treatment response. Both scoring systems have limitations but remain essential tools for clinicians in their respective specialties.