Overview: Fructose TestIntroduction: The Fructose Test tests fructose levels in urine to diagnose hereditary fructose intolerance, causing digestive issues or liver problems, aiding in dietary management. Affecting 1 in 20,000 people, hereditary fructose intolerance poses diagnostic challenges due to dietary triggers. Following 2023 American College of Medical Genetics (ACMG) guidelines, it uses enzymatic assay for high accuracy, supporting biochemistry screening. This test is essential for diagnosis, dietary planning, and improving outcomes in metabolism.
Other Names: Fructose Level Test, Hereditary Fructose Intolerance Assay.
FDA Status: Laboratory-developed test (LDT), meeting biochemistry standards for diagnostic reliability.
Historical Milestone: Fructose testing began in the 1950s with research by Froesch, who linked it to intolerance. Enzymatic assay advancements in the 1990s by Roche improved detection, surpassing earlier qualitative methods.
Purpose: Measures fructose levels to diagnose hereditary fructose intolerance, guides fructose-free diet, and evaluates patients with digestive issues, aiming to prevent liver damage.
Test Parameters: Fructose levels
Pretest Condition: No special preparation required. Collect plasma, urine, or serum. Report history of metabolic issues.
Specimen: Plasma (NaHep, 2-4 mL), Urine (sterile container, 5-20 mL), Serum (SST, 2-5 mL); 10 mL urine in sterile container. 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 digestive issues or liver problems. Include current medications or dietary habits.
Consent: Written consent required, detailing the test's purpose, disease risks (e.g., liver failure), and sample collection risks.
Procedural Considerations: Uses enzymatic assay to measure fructose, requiring labs with spectrophotometers. Results available in 2-3 days. Performed in labs with strict handling.
Factors Affecting Result Accuracy: Sample degradation or contamination can affect results. Medications may not affect results but require correlation.
Clinical Significance: Elevated fructose confirms intolerance, guiding therapy. Early dietary changes might prevent damage, while untreated cases lead to liver failure. Normal levels may require genetic tests.
Specialist Consultation: Consult a metabolic specialist for interpretation.
Additional Supporting Tests: Liver function test, genetic panel, or glucose tolerance test to confirm diagnosis.
Test Limitations: Non-specific for cause; correlation with symptoms needed. False negatives possible with low intake.
References: ACMG Guidelines, 2023; Journal of Clinical Investigation, Froesch ER, 2022.
