- Home
- Products
- Services
- Resources
- About Us
- News
- Contact
Views: 0 Author: Site Editor Publish Time: 2026-08-25 Origin: Site
Reliable immunohistochemistry depends on more than selecting an antibody against the correct target. Laboratories also need appropriate control materials to evaluate whether the staining result is specific, interpretable, and reproducible.
This is especially important for PSMA immunohistochemistry. PSMA is a widely studied prostate cancer biomarker, but its expression may vary between tissue samples, tumor regions, and assay conditions. Differences in fixation, antigen retrieval, antibody concentration, detection chemistry, and staining interpretation can all influence the final result.
A PSMA positive and negative 2-in-1 FFPE control standard provides two reference responses in one paraffin-embedded format. By placing positive and negative control materials within the same control design, laboratories can evaluate target-specific staining and background behavior under comparable staining conditions.
This article explains how combined PSMA FFPE controls support IHC assay development, validation, troubleshooting, and routine quality control.
A PSMA positive and negative 2-in-1 FFPE control contains both positive and negative reference materials in a paraffin-based format.
The positive component helps evaluate whether the antibody and detection system can produce the expected PSMA-associated signal.
The negative component helps assess non-specific staining and background.
Testing both responses in the same staining run supports more direct comparison.
FFPE controls are useful because they can reflect important steps in a laboratory’s routine tissue-processing and staining workflow.
Combined controls can support assay development, method validation, troubleshooting, and ongoing quality monitoring.
The control result should always be interpreted together with staining localization, signal intensity, tissue morphology, and the laboratory’s validated criteria.
PSMA is a membrane-associated protein encoded by the FOLH1 gene and is frequently studied in prostate cancer tissue. In an IHC assay, an antibody is used to detect PSMA-associated protein expression in a tissue section.
A PSMA positive and negative 2-in-1 FFPE control is designed to provide both types of reference material in one paraffin-embedded control format:
A positive material intended to produce a PSMA-associated staining signal
A negative material intended to show little or no target-specific signal
The two components provide a practical reference for evaluating the same staining workflow. Instead of assessing a positive control and a negative control under different conditions, laboratories can compare both responses within the same assay run.
This format is particularly useful when laboratories need a clear reference for distinguishing true target-associated staining from non-specific background.
A positive control and a negative control answer different questions.
The positive control helps determine whether the staining system can detect the target. If the positive area does not show the expected signal, the laboratory may need to review the antibody, antigen retrieval method, incubation conditions, detection reagent, or tissue-processing steps.
The negative control helps determine whether the staining system is producing unintended signal. If the negative area shows excessive staining, the result may be related to non-specific antibody binding, endogenous tissue activity, excessive detection signal, or other technical factors.
Using only one type of control may leave part of the assay performance unexamined. For example:
A positive result alone does not show whether background staining is controlled.
A negative result alone does not demonstrate that the assay can detect PSMA.
A combined positive and negative control provides a more complete view of staining behavior.
For PSMA IHC, this comparison is valuable because tissue staining may differ in intensity and distribution. The positive and negative responses provide a reference framework for interpreting the assay result.
A 2-in-1 format offers several practical advantages for laboratory workflows.
When positive and negative control materials are tested together, they are exposed to the same antibody dilution, antigen retrieval conditions, detection system, and incubation steps. This makes it easier to compare the two staining responses.
A combined control can reduce the need to manage multiple separate control materials. It provides a compact reference for reviewing positive signal, negative behavior, and background staining during the same test.
If the positive component is weak and the negative component remains clean, the laboratory may need to review sensitivity-related factors. If both positive and negative areas show strong staining, the laboratory may need to investigate non-specific background or detection-related issues.
A combined control can be used repeatedly to monitor whether staining performance remains consistent over time. Changes in positive intensity or negative background may indicate a shift in reagent performance, instrument conditions, tissue processing, or operator technique.
FFPE means formalin-fixed, paraffin-embedded. FFPE tissue is widely used in pathology and IHC workflows, making it a practical format for control materials intended to support tissue-based assay development.
An FFPE control can help laboratories assess not only antibody binding but also parts of the tissue-processing and staining workflow. Relevant factors may include:
Tissue fixation and processing
Paraffin embedding
Section preparation
Deparaffinization
Antigen retrieval
Primary antibody incubation
Detection chemistry
Counterstaining
Microscopic interpretation
Because these steps can influence staining quality, a control material that follows a tissue-compatible workflow may provide a more relevant reference than a control that does not reflect the laboratory’s usual testing format.
The specific performance of an FFPE control will still depend on the laboratory protocol and the antibody-detection system used. Control results should therefore be evaluated as part of the complete validated assay. Laboratories can review available IHC reference standards when selecting a control format for their workflow.
During assay development, laboratories need to compare different antibody concentrations, retrieval methods, incubation times, and detection conditions.
A combined PSMA positive and negative FFPE control can help laboratories assess how each change affects:
Positive staining intensity
Negative staining behavior
Background level
Signal-to-background separation
Staining consistency
This allows the laboratory to select conditions that provide a clear and reproducible staining pattern.
Before an assay is used for a defined research or testing purpose, its performance needs to be evaluated against established criteria. PSMA FFPE controls can support the assessment of analytical behavior under the selected workflow.
Depending on the validation plan, laboratories may review:
Expected positive response
Expected negative response
Repeatability
Reproducibility
Staining localization
Inter-run consistency
Sensitivity to protocol changes
The control material does not replace the laboratory’s validation plan. Instead, it provides a consistent reference for monitoring the assay during that process.
Unexpected PSMA IHC results may come from different sources. A weak signal may be related to tissue processing, antigen retrieval, antibody concentration, detection chemistry, or reagent degradation. Excessive background may have a different cause.
A positive and negative 2-in-1 control can help narrow down the problem by showing whether:
The target signal can still be detected
The negative region remains clean
The antibody is producing non-specific staining
The staining system is generating excessive background
The change affects both positive and negative responses
After an assay has been established, control materials can be used to monitor ongoing staining performance. Reviewing the control result in each relevant run can help laboratories identify gradual changes before they affect the interpretation of research samples or test specimens.
Routine monitoring may include recording:
Positive staining intensity
Negative background level
Staining distribution
Section quality
Run-to-run consistency
Any deviation from established acceptance criteria
The evaluation should include both the positive and negative components.
The positive area should show a clear and interpretable PSMA-associated staining signal under the selected assay conditions. Laboratories may assess the intensity, distribution, and localization of the signal.
The expected result should be defined according to the laboratory’s antibody, platform, detection system, and acceptance criteria.
The negative area should help laboratories determine whether non-specific staining or excessive background is present. A clean negative response makes it easier to distinguish target-related signal from technical artifacts.
The most useful information comes from comparing the positive and negative areas rather than reviewing either area in isolation. Laboratories can consider the separation between the expected positive signal and the negative background.
The result should be evaluated together with tissue morphology, section quality, staining localization, and the overall appearance of the slide. A control should support interpretation, but it should not be considered separately from the complete assay workflow.
When selecting a PSMA FFPE control, laboratories should consider the intended use and testing stage.
Important factors may include:
Whether the control contains both positive and negative reference materials
Whether the format fits the laboratory’s FFPE workflow
Whether the control supports assay development or routine QC
Whether the staining response is suitable for the intended antibody system
Whether the control can support repeat testing
Whether storage, handling, and sectioning requirements are clearly defined
Whether the supplier can provide relevant technical information
Laboratories may also need different control formats at different stages of development. For example, an assay developer may first need a control for optimization and later require a consistent reference for validation or routine monitoring.
For laboratories with target-specific control requirements, CB-Gene also provides customized IHC standards for research and assay development applications.
A PSMA positive and negative 2-in-1 FFPE control standard provides a practical reference for evaluating both target-associated staining and non-specific background in the same IHC workflow.
The positive component helps assess signal detection, while the negative component helps assess background and specificity. Used together, they can support assay development, method validation, troubleshooting, and routine quality control.
For laboratories working with PSMA IHC, selecting a control format that matches the intended FFPE workflow can make assay evaluation more consistent and easier to interpret.
Need a defined PSMA IHC control for assay development or quality monitoring?
Explore CB-Gene’s IHC reference standards or discuss your requirements for customized IHC standards.
It is a paraffin-embedded IHC control format that includes both positive and negative reference materials for evaluating PSMA staining performance.
The positive control helps confirm that the assay can detect PSMA-associated signal. The negative control helps assess non-specific staining and background. Using both provides a more complete view of assay performance.
A 2-in-1 control allows positive and negative responses to be evaluated under comparable staining conditions, which can support direct comparison and more efficient troubleshooting.
Yes. They can support the comparison of antibody conditions, antigen retrieval methods, detection systems, and other workflow parameters during PSMA IHC assay development.
Laboratories can monitor positive signal, negative background, staining distribution, and run-to-run consistency to identify changes in assay performance.
No. A control standard supports assay evaluation and monitoring, but it does not replace a laboratory’s complete validation plan, acceptance criteria, or documentation requirements.
