The following information is relevant to facilities wishing to include Paraffin In Situ Hybridization (ISH) testing on their current scope of accreditation.

Upon a written request for this addition, NATA will either review the information on-site at assessment as an extension to the scope of accreditation or conduct a desk top variation (DTV) if the request comes outside the routine assessment process.  Charges are levied for extensions to the scope of accreditation (in accordance with NATA's fee schedule current at the time) where additional effort is required e.g. where the request will require additional time on site during a routine reassessment or the conduct of a DTV outside a routine reassessment.  NATA staff will provide further advice following receipt of a request.

Types of ISH?
CISH (Chromogenic In Situ Hybridization) or SISH (Silver - ISH).
CISH is a manual method, whereas SISH is automated.

What is it and what is it used for?
These techniques allow detection of gene amplification, chromosome translocations and chromosome number on formalin-fixed, paraffin-embedded (FFPE) tissues (4-5 μm thickness) using conventional peroxidase reactions under the brightfield microscope.  Probe hybridization results may then be visualized within the context of the surrounding tissue morphology.

Pathologists can view tissue morphology and gene aberrations simultaneously.

What will be reviewed at assessment?:

Personnel
Each pathologist and scientist involved in this testing must have performed on-line training and be certified by Invitrogen to do CISH testing.  Certificates for those involved in testing will be sighted.  Pathologists are certified in testing and interpretation, scientists are certified in testing only.

Accommodation
No special accommodation is required.  Sample preparation may be performed in a cytogenetics department, as this is a process which may be performed in such laboratories.

However, results must be reported by an Anatomical Pathologist as morphology interpretation is required.

Laboratory equipment
A brightfield microscope is required.

Pre-examination procedures
The usual requirements for histology specimens apply.

Examination procedures
Records of verification of the assay must be available for review at  assessment.  As a minimum, the verification should show concordance between the laboratory's assay and externally performed CISH or FISH on at least 25 cases.

It is common for laboratories to modify the test kit to obtain optimal results.  Any deviation from the manufacturer's instructions must be validated.  Refer to Requirements for the Development and Use of In House In-Vitro Diagnostic Devices (IVDs) NPAAC.

Assuring quality of examination procedures
The CISH method provides an internal positive control which must be performed to confirm adequate method performance.  Laboratories should also consider including an additional 'weak' control.

Each reporting pathologist must enrol in a suitable CISH QAP program.

Measurement Uncertainty (MU) does apply to CISH testing and MU estimates must therefore be undertaken.  Even though results are quantitative, they are reported as qualitative.

Post examination procedures
The usual requirements for histology specimens apply.

Reporting of results
As mentioned above it is essential to have pathologist involvement in reporting.  Results are reported as positive or negative.

Desk Top Variation (DTV)
Laboratories wishing to have CISH/SISH included in their current scope of accreditation outside of the routine assessment cycle must make a written request to NATA.  The following information will be required to be submitted and will be forwarded for technical review:
Training certificates for staff and reporting pathologist(s);

• Current CISH/SISH method;
• Validation of assay, including MU estimates; and
• QAP CISH/SISH data.

The DTV will be chargeable at the current hourly rate which is available on the NATA website.
Should you have any questions please do not hesitate to contact Ms Megan Nelson, Manager, Medical Testing, NATA or Mr Andrew Griffin, Deputy Field Manager - Technical, Medical Testing, NATA.