Immunohistochemistry (IHC) is a trusted lab technique used to find specific proteins, or antigens, in tissue samples. By applying antibodies that latch onto target markers, IHC lets pathologists clearly identify different types of cancer and cellular abnormalities under a microscope.
How IHC Tells Diseases Apart
Under a standard brightfield microscope, many diseases may look indistinguishable. IHC solves this by picking up on the unique molecular markers found on certain cells.
The test works by washing specialized antibodies over a tissue sample. In standard IHC, these antibodies tie to enzymes that create a color change—usually brown or red—when they hit their target. Once the color develops, the target protein stands out. This is how pathologists pinpoint the exact disease and give doctors the exact information they need to plan treatments.
Common IHC Markers and Panels
Labs run specific antibody panels based on the suspected disease for accurate pathological answers. Some of the most frequently requested IHC markers include:
- HER2, ER, and PR: Routinely used to classify breast cancers and determine if a patient is a candidate for targeted hormone therapies.
- PD-L1: A major focus in modern drug development, used to predict if a tumor will respond to specific immunotherapies.
- Ki-67: A marker that measures cell proliferation, helping doctors understand exactly how fast a tumor is growing.
- PSA: Used to identify prostate-originating tissue, even if the cancer has spread to other parts of the body.
The Reality of Prep Work: Quality Control and Antigen Retrieval
Accurate IHC results don’t just happen. The process demands strict quality control, starting the moment a tissue sample leaves the operating room.
If a sample sits too long before formalin fixation, the target proteins degrade. Even well-preserved tissues usually require “antigen retrieval.” This is a delicate process of heating the sample or treating it with enzymes to unmask the proteins so the antibodies can actually reach them. Getting this prep work wrong leads to false negatives or high background staining, which is why having experienced lab technicians is non-negotiable.
Why Facilities Outsource IHC to Contract Labs
Setting up an in-house IHC department is incredibly expensive. Between buying automated staining platforms, stocking highly specific (and costly) antibodies, and hiring specialized pathologists to interpret the slides, the overhead adds up fast.
Because of this, hospitals, research clinics, and pharmaceutical companies frequently outsource IHC testing to specialized contract labs. This approach solves several operational problems:
- Managing overflow: Handling high volumes of slides when internal pathology departments get backed up to keep turnaround times short.
- Accessing rare antibodies: Tapping into specialized labs that already stock expensive or uncommon biomarker panels for niche research.
- Ensuring compliance: Making sure preclinical drug trials meet GLP standards, or that clinical diagnostics meet strict CLIA/CAP requirements.
- Confirming complex results: Providing a rock-solid second look to validate tricky pathology reports.
Need an Accredited Contract Lab for IHC Testing?
If your clinic or research team needs specialized IHC testing, we can help. Simply submit a lab request to connect with accredited, specialized labs on the Contract Laboratory network.
This article was created with the assistance of Generative AI and has undergone editorial review before publishing.
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