A failed IHC control and an attractive conclusion
An IHC run contains a patient section expected to answer a lineage question and the laboratory’s assigned control material. The patient slide is unstained, but the positive-control target also fails to appear. Tissue remains on both slides and the identifiers are correct. A trainee wants to report that the patient definitely lacks the target because the blank appearance is consistent with one suspected diagnosis. The antibody lot, retrieval record and detection reagents are available for review. The technologist must distinguish a technically uninterpretable negative result from demonstrated biological absence and avoid issuing a final diagnosis outside the qualified reporting process. The case does not prescribe one universal corrective buffer or stronger antibody concentration.
1. Can the patient’s target absence be concluded?
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No. The failed positive control means the run has not demonstrated that the assay could detect the target under these conditions.
2. What is the appropriate technical response?
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Investigate the documented assay stages, preserve the original results and resolve the failure through the validated process before qualified interpretation. Increasing a reagent blindly is not an evidence-based repair.