Ruisai Small Classroom: A Guide to the Analysis and Validation Principles of IHC Inspection

Recently, at the American CAP2014 Annual Meeting, the American College of Pathologists and Laboratory Quality Center issued a Principles of Analytic Validation of Immunohistochemical Assays, which was published in the recent Arch Pathol Lab Med magazine. , excerpts are as follows:

Guide statement

1. Recommendation: The laboratory must confirm the validation of all immunohistochemistry (IHC) test results before it can be used in the clinic.

Note: These means include (but are not limited to):

Compare new test results with morphology and expected results;

Compare the new test results with the previous test results of the same sample in the same laboratory (using the validated test plan);

Compare the new test results with the results of the same tissue sample in another laboratory (both using a validated test protocol);

The new test results are compared to previously validated non-immunohistochemical test results.

2. Recommendation: For each clinically validated test protocol (except for HER2/neu, ER and PgR, they already have clear validation guidelines), new tests and previous tests or expected laboratory results Must achieve at least 90% overall consistency. If the consistency is less than 90%, the lab needs to explore the reasons for the low consistency.

3. Expert consensus: For the preliminary analysis and verification of the non-predictive factor test program, the laboratory should test at least 10 positive and 10 negative tissue samples. If the laboratory chief physician believes that less than 20 verification samples are sufficient for certain markers (eg, rare antigens), the rationale for the decision is recorded.

Note: If a positive sample is present, the validation should include factors for high and low levels of expression, and for markers that require quantitative reporting, the expected range of clinical outcomes (expression levels) should be expanded.

4. Expert consensus: For the preliminary analysis and verification of all laboratory predictive marker testing protocols (except HER2/neu, ER and PgR), the laboratory should test at least 20 positive and 20 negative tissue samples. If the laboratory chief physician believes that there are fewer than 40 validated samples for a particular marker, then the rationale for the decision is recorded.

Note: The number of validated positive samples should be greater than the expected range of clinical outcomes (expression levels). This recommendation does not apply to any of the markers that already have separate verification guidelines.

5. Recommendation: For markers with both predictive and non-predictive dual characteristics, they should be used as predictive markers for laboratory validation.

6. Recommendation: If possible, the tissue specimens used for laboratory validation should be fixed and treated in the same manner as specimens used for clinical testing thereafter.

7. Expert consensus: For routine IHC testing of cytological samples that differ in the way they are treated in a tissue that has been validated (eg, ethanol-fixed cell mass, air-dried smear specimen, formalin-fixed) The laboratory should inspect a sufficient number of specimens to ensure that the test meets the desired objectives. The laboratory director is responsible for determining the number of positive and negative samples to be tested and the number of predictive and non-predictive markers to be tested.

8. Expert opinion: For routine IHC testing of decalcified tissue samples, the laboratory should test a sufficient number of these samples to ensure the desired results are achieved. The Laboratory Medical Director is responsible for determining the number of positive and negative tissues and the number of predictive and non-predictive markers to be tested.

9. Recommendation: The lab can use the entire slice, TMAs and / or MTBs for verification. If the TMAS/MTBs are not suitable for the target antigen or if the laboratory medical director cannot determine if the fixation and treatment of the TMAS/MTBs is similar to the clinical sample, then the entire section profile should be examined.

10. Expert opinion: When a new reagent batch is used in a clinically validated test protocol, the laboratory should use at least one known positive sample and one known negative sample to perform a performance test on the new reagent.

11. Expert opinion: When any of the following changes have been made to the verified test plan, the laboratory shall use at least 2 known positive samples and 2 known negative samples to confirm the performance of the test plan.

The changes are as follows:

Antibody dilution;

Antibody supplier changes (same clone);

Incubation or repair time changes (same method).

12. Expert opinion: The laboratory should inspect a sufficient number of samples to confirm the performance of the test plan to ensure that the expected results are consistently achieved when:

a fixed way;

Antigen retrieval methods (eg, changes in pH, different buffers, different heating platforms);

Antigen detection system;

Organize processing or inspection equipment;

Environmental conditions for testing (eg, laboratory relocation);

Laboratory water supply.

The Laboratory Medical Director is responsible for determining the number of predictive and non-predictive markers to be tested, as well as the number of positive and negative tissue specimens to be tested.

13. Expert opinion: When the antibody clone or the existing test program changes, the laboratory needs to perform a complete re-validation (equivalent to the initial analysis and verification) process.

14. Expert opinion: The laboratory must document all validation, verification and calibration procedures that meet regulatory and certification requirements.

pecification

-Probe Type: Consist by two of Convex, Microconvex, Linear, Small Linear, Transvaginal

-Scanning mode: Electronic array

-Display mode: B, B/M, color doppler version with B+Color, B+PDI, B+PW

-Probe element: 128/192

-Channel of RF circuit board: 32/64

-Probe frequency and scan depth, head radius/width, scan angle(convex):

Convex head 3.5MHz/5MHz, 90/160/220/305mm, 60mm, 60°

Convex head with phased array(cardiac) scan mode: 3.5MHz/5MHz, 90/160/220/305mm, 40mm, 90°

Linear head 7.5MHz/10MHz, 20/40/60/100mm, 40mm

Small Linear head 10MHz/14MHz, 20/30/40/55mm, 25mm

Microconvex head 3.5MHz/5MHz, 90/130/160/200mm, 20mm, 88°

Transvaginal head 6.5MHz/8MHz, 40/60/80/100mm, 13mm, 149°

-Image Adjust: BGain, TGC, DYN, Focus, Depth, Harmonic, Denoise, Color Gain, Steer, PRF

-Cineplay: auto and manual, frames can set as 100/200/500/1000

-Puncture assist function: the function of in-plane puncture guide line, out-of-plane puncture guide line, automatic blood vessel measurement.

-Measure: Length, Area, Angle, heart rate, Obstetrics

-Image save: jpg, avi and DICOM format

-Image frame rate: 18 frames/second

-Battery working time: 2.5 hours(according to whether keep scan)

-Battery charge: by USB charge or wireless charge, take 2 hours

-Dimension: L156×W60×H20mm(if with transvaginal head length is 270mm)

-Weight: 250g

-Wifi type: 802.11g/20MHz/5G/450Mbps

-Working system: Apple iOS and Android, Windows