CD45RO IHC with interpretation (pathology) Biomarker Testing
It measures CD45RO-positive memory T cells in tissue to help classify inflammation or lymphoma, with ordering and interpretation through Vitals Vault labs.
With Vitals Vault, you have access to a comprehensive range of biomarker tests.
CD45RO IHC with interpretation is not a blood test. It is a pathology test performed on a tissue sample (a biopsy or surgical specimen) to show whether immune cells in that tissue include CD45RO-positive T cells, which are commonly described as “memory” T cells.
This stain is usually ordered when a pathologist is trying to characterize an inflammatory infiltrate or help classify a suspected lymphoid (immune-cell) process. Your report is interpreted in the context of what the tissue looks like under the microscope and other immunostains.
Because it is tissue-based, the most important “prep” is not fasting or timing. It is making sure the right specimen is available and that the question being asked (for example, reactive inflammation vs a lymphoproliferative disorder) is clear.
Do I need a CD45RO IHC with interpretation test?
You may need CD45RO immunohistochemistry (IHC) if you have had a biopsy and the pathology team needs more detail about the immune cells present in the tissue. This often comes up when the microscope findings are not specific enough on their own, or when the pattern of inflammation needs to be better characterized.
CD45RO is commonly used as part of an immunophenotyping workup. In practical terms, it helps show whether a population of lymphocytes in the tissue is predominantly T cells with a “memory” phenotype, and whether those cells are distributed in a way that fits with a reactive (non-cancerous) process or supports a specific diagnosis when combined with other markers.
You might see this test ordered in evaluations involving enlarged lymph nodes, persistent masses, unusual skin or gastrointestinal biopsies, or other tissues where lymphocytes are prominent. It can also be used to help describe immune infiltration in chronic inflammatory conditions.
This test supports clinician- and pathologist-directed diagnosis and treatment planning, but it does not diagnose a condition by itself. The interpretation depends on the tissue type, the clinical story, and the full panel of stains performed.
CD45RO IHC is a CLIA-validated pathology assay performed on tissue sections; results are interpretive and must be correlated with histology and other immunostains, not used as a standalone diagnosis.
Lab testing
Order labs to measure CD45RO, IHC with Interpretation
from $335.35 at Quest Diagnostics
About 1 week
Schedule online — results typically within a week
Clear next steps
Guidance included, with follow-up care available
HSA / FSA
Eligible for pre-tax health spending accounts
Get this test with Vitals Vault
If you already have a tissue specimen being evaluated, Vitals Vault can help you order CD45RO IHC with interpretation as part of a pathology workup so your report includes both the stain result and a clear narrative of what it means in context.
You can use PocketMD to talk through your pathology wording, what “positive” or “negative” means for your situation, and which companion stains or labs are commonly paired with CD45RO when the goal is to classify a lymphoid infiltrate.
If your next step is broader lab mapping (for example, ruling out infection, assessing inflammation, or monitoring treatment), you can also coordinate additional lab orders through Vitals Vault so your follow-up testing is organized and easy to track over time.
- Orderable lab testing with results you can save and trend in one place
- PocketMD support to translate pathology language into next-step questions
- Designed to complement—not replace—your clinician’s care plan
Key benefits of CD45RO IHC testing
- Clarifies whether lymphocytes in a biopsy include CD45RO-positive (memory) T cells.
- Helps characterize inflammatory infiltrates when routine microscopy is not specific enough.
- Supports lymphoma and lymphoproliferative workups when interpreted alongside other immunostains.
- Adds context about immune-cell distribution (where the cells are in the tissue), not just whether they are present.
- Can help distinguish reactive immune responses from patterns that warrant deeper hematopathology review.
- Improves communication between your clinical symptoms and the pathology report by tying findings to a written interpretation.
- Makes it easier to plan follow-up testing by identifying which companion markers may be most informative next.
What is CD45RO IHC with interpretation?
CD45RO is a protein found on the surface of many T lymphocytes, especially T cells that have previously been activated and are often referred to as “memory” T cells. Immunohistochemistry (IHC) is a staining method that uses antibodies to highlight specific proteins in a thin slice of tissue, allowing a pathologist to see which cells express the marker and how those cells are arranged.
“CD45RO IHC with interpretation” typically means two things are provided: (1) the technical stain result (for example, which cells are positive and how strong the staining is), and (2) an interpretive comment that explains what the staining pattern suggests when combined with the tissue’s microscopic appearance and any other stains performed.
CD45RO is not usually interpreted in isolation. It is often considered alongside other T-cell markers (such as CD3), B-cell markers (such as CD20), and additional markers chosen based on the differential diagnosis. The goal is to build an immunophenotypic picture that matches—or does not match—the suspected condition.
What the stain is actually showing
The stain highlights CD45RO expression on lymphocytes within the specimen. Your report may describe the percentage of cells staining, the intensity (weak/moderate/strong), and the pattern (diffuse, patchy, perifollicular, epidermotropic, etc.), because pattern can matter as much as positivity.
Why interpretation matters more than a single word like “positive”
In many tissues, some CD45RO-positive T cells are expected, especially when there is inflammation. A “positive” result can be normal for the situation, while an unusual distribution or an atypical accompanying marker profile may be what raises concern. The interpretive note is where the pathologist connects the stain to the diagnostic question.
What do my CD45RO IHC results mean?
Low or absent CD45RO staining
Low or absent CD45RO staining generally means few memory-type T cells are identified in the areas examined. Depending on the tissue and the clinical question, that can be reassuring, expected, or simply indicate that other immune-cell types are more prominent. It can also occur if the infiltrate is primarily B cells, plasma cells, or non-lymphoid cells. Your pathologist will usually interpret this alongside a broader marker set to avoid over-calling a technical or sampling limitation.
Expected CD45RO staining for the tissue context
An “expected” pattern means the amount and distribution of CD45RO-positive T cells fits with what is commonly seen for that tissue and the degree of inflammation present. In reactive conditions, CD45RO-positive cells may appear in predictable locations and mix with other immune cells. When the interpretation states the pattern supports a reactive process, it usually means the stain result matches the overall benign microscopic picture. If you have symptoms, this can still be clinically meaningful, but it points your next steps toward identifying triggers rather than a primary lymphoid malignancy.
High CD45RO staining or a prominent CD45RO-positive infiltrate
High CD45RO staining means a large proportion of the lymphocytes in the sampled area are CD45RO-positive T cells, or the stain is strong and widespread. This can be seen in chronic or active inflammation, certain autoimmune-pattern reactions, and in some T-cell–predominant lymphoid processes. A high result is not automatically cancer, but it often prompts correlation with other T-cell markers and, when appropriate, additional studies to assess clonality or atypia. The key is whether the staining pattern and the rest of the immunostain panel fit a reactive explanation or suggest a specific lymphoid diagnosis.
Factors that influence CD45RO IHC results
Your result can be influenced by where the biopsy was taken, how much of the lesion was sampled, and whether the most involved area was captured in the tissue sections used for staining. Technical factors such as fixation time, antigen retrieval, and antibody performance can affect staining intensity. The underlying condition also matters: acute vs chronic inflammation, infection, medication effects (including immunosuppressants), and prior therapy can change the mix of immune cells present. Because of these variables, CD45RO is most reliable when interpreted as one piece of a coordinated pathology workup.
What’s included
- Cd45Ro, Ihc W/Interp
Similar tests you may see ordered
Frequently Asked Questions
Is CD45RO IHC a blood test?
No. CD45RO IHC is performed on a tissue sample (biopsy or surgical specimen). It stains cells in the tissue to show which ones express CD45RO and how they are distributed.
What does CD45RO positive mean on a pathology report?
It means the antibody stain detected CD45RO on cells in the tissue, most often T lymphocytes with a memory phenotype. Whether that is expected or concerning depends on the tissue type, the amount and pattern of staining, and the results of other immunostains.
Does a high CD45RO result mean lymphoma?
Not by itself. A prominent CD45RO-positive infiltrate can occur in chronic inflammation and many non-cancerous conditions. Lymphoma evaluation depends on the full microscopic picture plus a panel of markers (often including CD3, CD20, and others) and sometimes additional studies.
Do I need to fast or stop medications before CD45RO IHC?
Fasting is not relevant because this is a tissue stain, not a blood draw. Medications can influence immune-cell patterns in tissue, so it helps to ensure your clinician and pathologist know about steroids, immunosuppressants, chemotherapy, or biologic therapies you are using.
How long does CD45RO IHC take to come back?
Turnaround time varies by lab workflow and whether additional stains are added after the initial review. Many IHC stains are completed within a few business days once the specimen is in the lab, but complex cases can take longer if more markers or specialist review is needed.
What other stains are commonly ordered with CD45RO?
It depends on the diagnostic question, but CD45RO is often interpreted alongside broad T-cell markers (like CD3), B-cell markers (like CD20), and other targeted markers selected by the pathologist based on what the tissue shows. Your report may list the full immunostain panel used for your case.