Not enough tissue for testing — what happens next

Most commonly because the biopsy was small to begin with. A fine-needle aspiration or core-needle biopsy yields only a limited amount of tissue, and some of it is usually used up first — confirming that the cells are cancerous and identifying the cancer subtype — before biomarker testing such as PD-L1 is even ordered. By the time the request reaches the lab, what's left on the slide may not have enough viable tumour cells to generate a dependable score.

A handful of other reasons show up regularly too: the sample may be mostly necrotic tissue, blood, or inflammatory cells rather than tumour; it may have been crushed or poorly preserved on its way to the lab; or, for bone-involving cancers, the specimen may have been treated with a decalcifying acid that can degrade the DNA and protein a test needs to read. Pathology guidelines set a minimum bar for viable tumour cells before a result can be trusted, per NCCN and ASCO guidance on biomarker testing. When a sample falls short of that bar, an accredited lab reports it as 'insufficient tissue' or QNS (quantity not sufficient) rather than issue a score that might not be reliable.

This is a frequent, frustrating dead end for patients holding a report full of numbers that suddenly has a blank where the most important one should be — and it usually has more than one workable solution, explained below.

Which option applies to you depends on your cancer type, where tissue is stored, and what your oncologist still needs to know — this table is for general orientation, not a recommendation for your case.

In short: a liquid biopsy can often keep other parts of your workup moving while a tissue question is being resolved, but it is a complement to tissue testing for PD-L1, not a substitute for it. Research into blood-based PD-L1 assessment is ongoing, and evidence isn't yet mature enough to treat it as equivalent — your oncologist will tell you plainly if and when that changes.

1. 1

   Ask exactly what "insufficient" means for your sample

   Ask whether it was quantity (too little tissue) or quality (too few viable tumour cells, or degraded material) — the reason affects which alternative makes sense.

2. 2

   Check whether any tissue block still exists

   Your treating hospital or the lab that ran the original diagnosis can confirm whether a re-cut or an archival block from a previous procedure is available.

3. 3

   Ask which markers still need answering

   If PD-L1 specifically is missing but other genomic markers matter for your treatment plan, a liquid biopsy may be able to fill some of those gaps while the tissue question is resolved.

4. 4

   Discuss timing with your oncologist

   Ask how long the chosen route will realistically take, and whether waiting for that result changes anything about when treatment can start.

Sometimes the tumour site that would need to be re-sampled is hard to reach, close to sensitive structures, or the patient's general fitness makes a second procedure riskier than the information gained is worth. In that situation, your oncologist and radiologist will usually look at whether a different, more accessible site can be sampled instead, whether a liquid biopsy can cover the genomic markers that matter most for the specific treatment being considered, or whether it is reasonable to proceed with the information already available.

This is a case-by-case clinical judgement weighed against your full picture — stage, prior treatment, overall health and the specific decision at hand — not a fixed rule that applies the same way to every patient.

• Do You Need a Repeat Biopsy Before Starting Immunotherapy? — a closer look at when oncologists actually recommend re-sampling, and when they don't.
• Genetic and Genomic Reports: Reading the Summary Page — once a usable sample exists, this walks through what the resulting report actually says.
• Where to Get Biomarker Testing Done in Hyderabad — how CION coordinates testing with accredited partner pathology labs.
• Immunotherapy at CION Cancer Clinics — the full picture of how CION supports patients through the immunotherapy decision and journey.

This page explains general terminology around insufficient-tissue results for education only and does not interpret any individual patient's report. Biomarker testing is coordinated at accredited partner pathology laboratories. Bring your report to a consultation for a doctor's assessment of what it means for you.

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An 'insufficient tissue' report can feel like a dead end. Our oncologists explain what it actually means and the fastest safe way forward.