[Creatine kinase "NAC-activated": reference values for children (author's transl)]

Area of Science:

• Biochemistry
• Pediatric Medicine
• Clinical Chemistry

Context:

• Establishing accurate reference ranges for serum creatine kinase (CK) is crucial for diagnosing various pediatric conditions.
• Existing methods for CK determination may lack precision, necessitating revised standard procedures.
• The revised standard method utilizes N-acetylcysteine (NAC) activation for enhanced reliability.

Purpose:

• To establish age-specific reference values for serum creatine kinase (CK) activity in children aged 1 day to 15 years.
• To validate a revised standard method for determining serum CK activity using N-acetylcysteine (NAC) activation.
• To assess the influence of age and sex on serum CK levels in the pediatric population.

Summary:

• Reference values for serum creatine kinase (CK) activity were determined for 327 children (1 day to 15 years) using a revised standard method with N-acetylcysteine (NAC) activation.
• Serum CK activity showed no significant sex-dependence but varied markedly with age.
• Suggested upper limits for serum CK at 25°C are: neonates (1-3 days) ≤370 U/l, (4-10 days) ≤200 U/l, (11-31 days) ≤100 U/l; and children (2 months-15 years) ≤90 U/l.

Impact:

• Provides essential age-specific reference ranges for serum CK, aiding in the diagnosis and monitoring of pediatric neuromuscular and cardiac disorders.
• The revised NAC-activated method offers a more reliable tool for clinical laboratories assessing pediatric creatine kinase levels.
• Facilitates improved clinical decision-making by offering precise diagnostic benchmarks for serum CK in children.