Inconclusive and Discordant Results

#Uncertain is not the same as negative

MedlinePlus describes an inconclusive result as one that is not clearly positive or negative. STARD also distinguishes indeterminate findings and failures to complete a test, including technical failures or an insufficient sample. Those situations should not be silently converted into a negative finding.

The precise meaning of labels such as equivocal, inconclusive or invalid depends on the test and its report. Reading the report’s definition is more useful than assuming that every label describes the same problem. None of these words alone establishes whether a person has the target condition. This page explains types of uncertainty, not a rule for interpreting a particular report.

Evidence: MedlinePlus: understanding lab results / STARD 2015: explanation and elaboration

#Disagreement does not name the correct answer

Discordant findings disagree. A comparison might show one test positive and another negative, but that observation alone does not identify which result is correct. FDA explains that disagreement with a comparator that is not a reference standard can reflect limitations in either method. Even agreement between two tests does not rule out both being wrong.

STARD asks authors to describe the target condition, procedures, thresholds and reference standard. Differences in these definitions or in the information available to readers can affect the comparison. Ask whether the tests were evaluating the same question under comparable conditions before treating disagreement as proof of a technical mistake or a settled diagnosis.

Evidence: FDA: reporting diagnostic test performance / STARD 2015: explanation and elaboration

#Keep difficult results in the evidence

In a research report, the frequency and handling of indeterminate, missing and failed tests help readers understand feasibility and performance. STARD warns that excluding such results can bias accuracy estimates when the missingness or uncertainty is not random. A report should state how the analysis dealt with them, rather than presenting only the easy positive and negative cases.

FDA also cautions against estimating accuracy by resolving only the discrepant results and revising the comparison table. That approach can leave agreement between two incorrect results unexamined. These are study-appraisal principles. They are not instructions to repeat a patient’s test or to assign an uncertain finding to whichever category seems safer.

Evidence: STARD 2015: explanation and elaboration / FDA: reporting diagnostic test performance

#Communicate what remains unresolved

An uncertain result needs interpretation in the context of why the test was done, the report and the other information available to the clinical team. MedlinePlus explains that symptoms, history and examination findings are part of that picture. The appropriate assessment is not supplied by the uncertainty label itself.

The 2025 SAFER guide separates result acknowledgment from follow-up and recommends documentation of patient communication and any required next step. A clear account distinguishes what the test found, what it did not establish and what remains open. This page does not choose further tests, set an urgency window, diagnose a condition or recommend a treatment; those decisions require appropriate clinical review.

Evidence: MedlinePlus: understanding lab results / ASTP/ONC: 2025 SAFER result reporting and follow-up

Source note

The sections above were checked against the linked sources. No clinical review has been performed. This is general research education, not a clinical guideline.