provides clinical information for diagnostic for An above-normal level of succinylacetone in urine is diagnostic_for type 1 tyrosinemia, while an above-normal level of 4-hydroxyphenylpyruvate is diagnostic_for either type 2 or type 3 tyrosinemia. https://orcid.org/0000-0001-5809-9523 A relationship between a biomarker 'b' and a disease or condition of clinical interest 'd', where the presence or occurrence of 'b' is used to infer the presence or occurrence of 'd' or determine its subtype. Basis: This relation is based on the 'BEST' classification of and definition for 'biomarker', as given by the FDA-NIH Biomarker Working Group: A defined characteristic that is measured as an indicator of normal biological processes, pathogenic processes, or biological responses to an exposure or intervention, including therapeutic interventions. The BEST classification includes diagnostic, prognostic, susceptibility/risk, monitoring, predictive, safety, and pharmacodynamic/response biomarkers. See PMID:29405771 for details. Note that any given biomarker can be of a different type in different contexts. A below-normal level of creatine in cerebrospinal fluid is diagnostic_for guanidinoacetate methyltransferase deficiency, which is to say that such levels indicate that the patient has the indicated clinical issue. Darren A. Natale