NordiQC Seminar in Diagnostic Immunohistochemistry 2025
17–19 Sep 2025: Aalborg, Denmark
Check out our FAQ (Frequently asked questions) or contact us
The Nordic immunohistochemical Quality Control (NordiQC) quality assessment scheme provides fully comprehensive service consisting of:
  • Assessment of tests of immunohistochemical stains on NordiQC multitissue block sections
  • A general review of each assessment run on the website including:
    • photos of optimal and insufficient stains with explanations and hints for improvement
    • recommendations for optimizing staining protocols
    • examples of complete protocols for optimal staining of each epitope
  • Individual results including
    • assessment scores for each stain (certificate of participation for proficiency testing)
    • explanation of probable causes of insufficient (borderline or poor) stains
    • recommendations for improvement - tailored guidelines for the platform used
    • e-mail alerts and information about new runs, website updates etc.
  • Participant help line by e-mail (Contact)
  • Workshops and conferences

The General module comprises three annual runs with IHC tests for about 16 different antigens to be detected in formalin fixed paraffin embedded tissues. The antigenic markers are selected to cover a spectrum of commonly used as well as selected special or new markers.

The Breast cancer IHC module comprises two annual runs with IHC tests for HER-2 and Estrogen receptor or Progesterone receptor (alternating), and optionally one other IHC marker, e.g., Ki67.

The HER-2 ISH module comprises two annual runs with in situ hybridization (ISH) tests for HER-2 in breast cancer (without immunohistochemistry). This module comprise CISH/SISH test for HER-2 to be detected in formalin fixed paraffin embedded tissues. FISH test is also included (NordiQC assessment of lab scoring only).

The Companion module comprises two annual run which IHC test for PD-L1.

Currently all pathology laboratories performing immunohistochemistry are invited to participate in the quality assessment of immunostains. Laboratories may apply for enrolment in the general module, the breast cancer module and/or the HER2-ISH module. To enrol for the first time, the laboratory must fill out the electronic form on

Participant data and individual assessment results are anonymous to all but the NordiQC staff. By appointment with the laboratories, individual assessment results may be passed on to scientific boards. Individual results will not be given to sponsoring companies.

Data from the public available and uploaed assessment reports can be used with clear indication of origin to NordiQC. It is not allowed to change the content.

The laboratories enrolled are given a unique identification number, which is used for all assessments. All participating laboratories are registered in a password protected database. On the website, the laboratories have direct access to their own data and are solely responsible for keeping names, e-mail addresses, accounting information etc. up-to-date.

By submitting protocols electronically for one or more markers in a run announced, the enrolled laboratory automatically is considered a participant in the scheme for the rest of the year. Participation in NordiQC is an on-going subscription automatically renewed each year. Laboratories not submitting protocols for the first run in the annual scheme (deadline in the beginning of January) and not responding to a reminder, will have their participation closed without further notice. It can be reopened by request. Laboratories not submitting protocols for the second and third run in the annual scheme (deadlines usually about 4th April and 12 September, resp.) and not responding to reminders, will have their participation closed without further notice. It can be reopened by request.

Partcipants can follow the scheme, time lines and markers offered in the head box - modules - at NordiQC always strive to include relevant markers based on market trends, new Ab clones and assays. For this reason, included markers are subject to change during the year and participants encouraged to check the module section. 
Assessment method

1) Pathology laboratories enrolled in the scheme participate in an assessment run by staining slides circulated from NordiQC. The laboratories can only obtain unstained slides from NordiQC after electronic submission of relevant protocols before the deadline, filling out the relevant protocol on Protocols sent via e-mail or letter are NOT accepted. Submitted protocols can be editing up until assessment and will be locked hereafter.

2) Only the stains listed at a particular run can be submitted for assessment. If a laboratory does not stock an antibody needed for the detection of an epitope, it cannot be replaced by another antibody. This is due to the design of multitissue blocks and the need for a large number of comparable stains in order to make a proper assessment. For the same reason, stains are not assessed if inappropriate (irrelevant) antibodies have been used.

3) The sections circulated are serial sections cut from multitissue blocks containing several anonymized normal and tumour tissues fixed in 10% neutral buffered formalin and embedded in paraffin. NordiQC only sends out medical glass slides with fixed tissue. It is certified that this material is non-hazardous, non-contagious and non-infectious, and is of no commercial value. The tissues are selected to represent the purpose of the immunohistochemical analysis and contain clinical and critical relevant expression levels of the target analyte. The expected expression levels are characterized by NordiQC immunohistochemical reference methods and performed on different levels in the multitissue blocks to monitor the homogeneity and identify any heterogeneity in the circulated material. The expression levels are confirmed before circulation of the unstained sections and at end final day for slide return. For each epitope two (and only two) unstained sections are sent to laboratories, which have submitted protocols before the announced deadline. Accompanying letters containing basic information (setup of TMA and tissues included, deadline for submission etc.) can be found on Dates for slide circulation can be found at (Link).

4) Laboratories are requested to stain the slides using their standard protocol. One (and only one) slide for each epitope should be submitted to NordiQC for assessment. The other NordiQC slide should be kept in the laboratory as a reference (or as a reserve in case of a staining failure). In case slides are broken at the receipt, NordiQC should be contacted by e-mail.

5) All stained slides returned to NordiQC are assessed and marked by the assessor group. Generally, the assessment is based on the staining intensity and distribution in cells expected to stain, background staining, signs of cross-reactivity, counter-staining and tissue preservation during the staining process. Detailed assessment criteria and expected results are indicated on the general assessment report for each marker. 

The assessment of each participant’s slide is conducted by projecting the participant’s slide via a microscope to a monitor. The slide is then directly compared to the result obtained by the NordiQC reference method and show at a second monitor. All NordiQC slides both reference and circulated slides being used in an assessment are numbered and hereby both the reference slide nearest to the participant’s slide and the submitted result can directly be compared with minimal risk of change in expected expression pattern caused by heterogeneity or similar affecting the outcome and if occurring this will be taken into account when evaluating the slides. If the participant's slide are damaged or in case of lack of critical materials and cannot be assessed, the participant will be notified in the individual assessment report. 

6) Submitted stains are stored in a NordiQC archive for future documentation. The laboratories may request the stains for review - but they must be returned to NordiQC.

7) Examples of optimal and suboptimal staining results are uploaded on the website as of the date indicated on the modules page. Among protocols with optimal results, several are presented anonymized as recommended protocols. They are selected to reflect a spectrum of antibodies and methods and to represent different participating laboratories.

8) The NordiQC lab informs all participants about their individual scores via e-mail. In case of a borderline or poor staining result, suggestions for protocol optimization are given. In some cases comments are given also to good stains, e.g., in case of excessive counter-stain.

9) Laboratory proficiency tests in NordiQC are restricted to the runs. Due to limitations in staff and material it is not possible for laboratories to obtain individual tests outside the runs.

Assessment marks
Provided the use of an appropriate antibody, each stain is marked as optimal, good, borderline or poor.
  • Optimal staining: The staining is considered perfect or close to perfect in all of the included tissues.
  • Good staining: The staining is considered fully acceptable in all of the included tissues. However, the protocol may be optimized to ensure the best staining intensity and signal-to-noise ratio.
  • Borderline staining: The staining is considered insufficient, e.g., because of a generally too weak staining or a false negative staining of one of the included tissues, or a false positive staining reaction. The protocol should be optimized.
  • Poor staining: The staining is considered very insufficient e.g., because of false negative staining of several of the included tissues, or a marked false positive staining reaction. An optimization of the protocol is urgently needed.
Moderate or strong false positive staining due to, e.g., endogenous biotin is not compatible with an optimal staining.

In case of borderline or poor marks, the laboratory may request an immediate reassessment of the original stain, or a later reassessment based on a new stain in a following run.

Reassessment of the original stain: If a participant disagrees with borderline or poor marks given, or wishes a more elaborate motivation, a request should be e-mailed to NordiQC. The stain will then be reanalysed within 2-3 weeks to make sure that no error has happened and supplementary documentation for the marks provided.

Reassessment based on a new stain: If a participant wishes to document improvement, e.g., after correcting an error or changing the protocol, two new unstained sections may be obtained from NordiQC for a new staining in the run after next (two runs ahead).

To obtain new unstained slides, the participant must fill out a new protocol form before the deadline for the run in which the reassessment is carried out. The new slides are sent together with the slides for the next run and the stains will be included for assessing at the assessor meeting. Due to limited capacity, reassessment can only be carried out once per test and only for tests included in the latest accomplished run. If the test is already included in the following run (HER2 IHC, ER, PD-L1 and HER2 ISH), reassessment based on a new stain cannot be requested.