Analytical specificity: (i) This section should describe interference and cross reactivity studies to determine the analytical specificity, defined as the ability of a measurement procedure to detect or measure only the analyte (measurand) to be detected, in the presence of other substances/agents in the sample. (ii) Provide information on the evaluation of potentially interfering and cross reacting substances/agents on the assay. Information should be provided on the substance/agent type and concentration tested, sample type, analyte (measurand) test concentration, and results. (iii) Interferents and cross reacting substances/agents, which vary greatly depending on the assay type and design, could derive from exogenous or endogenous sources such as: (a) substances used for patient treatment (e.g. therapeutic drugs, anticoagulants, etc.); (b) substances ingested by the patient (e.g. over the counter medications, alcohol, vitamins, foods, etc.); (c) substances added during sample preparation (e.g. preservatives, stabilizers); (d) substances encountered in specific specimens types (e.g. hemoglobin, lipids, bilirubin, proteins); (e) analytes of similar structure (e.g. precursors, metabolites) or medical conditions unrelated to the test condition including specimens negative for the assay but positive for a condition that may mimic the test condition (e.g. for a hepatitis A assay: test specimens negative for hepatitis A virus, but positive for hepatitis B virus).Explanation : Interference studies involve adding the potential interferent to the sample and determining any bias of the test parameter relative to the control sample to which no interferent has been added.