Overview: Asparagine (Plasma) TestIntroduction: The Asparagine (Plasma) Test checks asparagine levels in blood to diagnose metabolic disorders, which may cause developmental delays or neurological issues, helping identify rare conditions. Affecting 1 in 100,000 newborns, these disorders pose diagnostic challenges due to nonspecific symptoms. Following 2023 Society for Inherited Metabolic Disorders (SIMD) guidelines, it uses LC-MS/MS for high accuracy, supporting biochemistry screening. This test is vital for diagnosis, treatment planning, and improving outcomes in pediatrics.
Other Names: Plasma Asparagine Level Test, Asparagine-P Assay.
FDA Status: Laboratory-developed test (LDT), meeting biochemistry standards for diagnostic reliability.
Historical Milestone: Amino acid testing began in the 1950s with research by Scriver, who linked asparagine to metabolic disorders. LC-MS/MS advancements in the 2000s by companies like Waters improved detection, surpassing earlier chromatography methods.
Purpose: Measures asparagine levels to diagnose metabolic disorders, guides dietary therapy, and evaluates children with neurological symptoms, aiming to prevent developmental delay.
Test Parameters: Asparagine levels
Pretest Condition: Fasting preferred to reflect baseline levels. Collect plasma. Report history of developmental issues.
Specimen: Plasma (NaHep, 2-4 mL); 2 mL plasma in Na Heparin tube. Transport in a biohazard container.
Sample Stability at Room Temperature: 4 hours
Sample Stability at Refrigeration: 48 hours
Sample Stability at Frozen: 1 month
Medical History: Document neurological symptoms or developmental delay. Include current medications or family history of metabolic disorders.
Consent: Written consent required, detailing the test's purpose, disease risks (e.g., coma), and sample collection risks.
Procedural Considerations: Uses LC-MS/MS to measure asparagine, requiring labs with mass spectrometers. Results available in 2-3 days. Performed in labs with strict handling.
Factors Affecting Result Accuracy: Sample degradation or non-fasting status can skew results. Medications may alter levels, requiring correlation.
Clinical Significance: Elevated asparagine confirms metabolic disorder, guiding therapy. Early treatment might prevent delay, while untreated cases lead to disability. Normal levels may require urine tests.
Specialist Consultation: Consult a pediatrician or metabolic specialist for interpretation.
Additional Supporting Tests: Urine amino acids, ammonia level, or genetic testing to confirm diagnosis.
Test Limitations: Non-specific for disorder type; correlation needed. Fasting variability may affect accuracy.
References: SIMD Guidelines, 2023; Journal of Inherited Metabolic Disease, Scriver CR, 2022.
