Which final result category describes a result that is not clearly positive or negative and may require retesting?

• A. Negative
• B. Positive
• C. Inconclusive
• D. Invalid

Answer: (C)

Not clearly positive or negative and needing a retest is described as inconclusive. This category covers results that sit near the decision threshold or have ambiguous data due to borderline signals, mixed results, or specimen quality issues. Because the result isn’t definitively positive or negative, the standard next step is to repeat the analysis, often with a new specimen or using a different method, to obtain a definite interpretation.

A negative result means no substances detected above the established cutoffs, a positive result means drugs are detected above those cutoffs, and an invalid result indicates a procedural or instrument problem that prevents any interpretation.