Establishment and application of immunohistochemical positive controls: Based on tissue fragment suspensions and tissue microarrays

Objective This study aims to explore the establishment of positive controls for immunohistochemistry (IHC), involving two distinct methods—tissue fragment suspensions and tissue microarrays—and evaluate their application value in improving the accuracy and reliability of pathological diagnosis. Methods A variety of residual human tissue samples (including tonsil, appendix, stomach, liver, kidney, intestine, thyroid, placenta, breast, and tumor tissues with known positive target antigens) were collected from June 2023 to August 2023. After standardized processing, tissue paraffin blocks were prepared. Internal laboratory positive controls were constructed using tissue fragment suspension technology and tissue microarray technology, respectively. In subsequent IHC assays, test tissues and corresponding positive control tissues were mounted on the same glass slide for simultaneous staining. The two methods were evaluated in terms of preparation efficiency, operational convenience, staining consistency, antigen stability, and quality control reliability. Results A long-term usable internal quality control reference for the laboratory was successfully established. Tissue fragment suspensions saved time and effort, significantly improving work efficiency; tissue microarrays, when applied to IHC detection related to targeted therapy, remarkably enhanced the accuracy of test results. Conclusion The IHC positive control quality control system established based on tissue fragment suspensions and tissue microarrays is economical, convenient, efficient, and reliable. It not only effectively ensures the accuracy of IHC results but also realizes the standardization of internal quality control. Particularly suitable for promotion and application in daily diagnostic work, this system holds important clinical value and practical significance.