Please follow the below specimen guidance to ensure efficient processing of cancer test requests.
For solid cancer testing we accept formalin-fixed paraffin-embedded (FFPE) slides. Please do not submit specimens processed in non-formalin fixatives such as Bouin’s, B-5 or acids.
We cannot accept blocks for testing - any sample sent as tissue blocks will be returned.
The specimen requirements for each test are given below:
| Test Type | No. H&E stained slides | No. unstained slides | Thickness of sections (um) | Recommended tumour purity*** |
|---|---|---|---|---|
| NGS panel | No. H&E stained slides 1* | No. unstained slides 8 | Thickness of sections (um) 5 | Recommended tumour purity*** ≥20% |
| MGMT promoter Methylation | No. H&E stained slides 1* | No. unstained slides 8 | Thickness of sections (um) 5 | Recommended tumour purity*** ≥50% |
| MLH1 promoter Methylation | No. H&E stained slides 1* | No. unstained slides 8 | Thickness of sections (um) 5 | Recommended tumour purity*** ≥30% |
| Microsatellite instability (MSI) | No. H&E stained slides 1* | No. unstained slides 8 | Thickness of sections (um) 5 | Recommended tumour purity*** ≥20% |
| Homologous Recombination Deficiency (HRD) | No. H&E stained slides 1* | No. unstained slides 8 | Thickness of sections (um) 5 | Recommended tumour purity*** ≥30% |
| Identity testing** | No. H&E stained slides 1* | No. unstained slides 8 | Thickness of sections (um) 5 | Recommended tumour purity*** Any |
| FISH | No. H&E stained slides 1* | No. unstained slides 2 per probe requested | Thickness of sections (um) 2 | Recommended tumour purity*** Any |
| Clinical Genetics Testing | No. H&E stained slides 1* | No. unstained slides 8 | Thickness of sections (um) 5 | Recommended tumour purity*** Non-neoplastic tissue required (i.e. no tumour content) |
*Please ensure that the H&E stain is used for section no. 4 or 5 from the middle of the serial
** A reference sample will be required (preferably peripheral blood) for comparison
*** The tumour purity refers to the percentage of nucleated cells in the field that are tumour cells and does not relate to the whole area.
Marking specimens
Please find below a downloadable guide to choosing the appropriate sample for testing:
Please note that:
- If FISH and NGS are both required, and the tumour percentage is >20%, please still mark a ~9mm area for the FISH testing.
- For MGMT testing the tumour percentage must exceed >30 %
- If the entire tissue section on the slide exceeds >20% tumour and therefore does not require marking, please mark ‘whole slide’ on the test order form. Do not leave the marking indication blank.
- In the rare cases where it is not possible to provide tumour percentage to >20 % (or exclude contaminant) in marked areas, testing may still be possible. In these cases, please indicate the tumour cell percentage on the test order form.
Additional guidance on form completion is provided on our ordering page.
Further training regarding tumour assessment is available from the genomics education programme (opens in a new tab).