If you have had a Pap test, a fine needle aspiration, or a procedure to sample fluid from around your lungs or in your abdomen, the report you received was likely a cytology report. Cytology reports are different from the tissue-based pathology reports most people are familiar with — they are based on the examination of individual cells rather than pieces of tissue, and they use a different vocabulary and a different set of result categories.
This article explains what a cytology report is, how it differs from a standard pathology report, what types of procedures produce cytology results, and how to interpret the most common terms and result categories you may see.
Cytology is one of several types of pathology reports you may receive. Other common types include surgical pathology reports (produced after a biopsy or surgery in which a piece of tissue is removed), hematopathology reports (produced after examination of blood, bone marrow, or lymph node samples to diagnose blood diseases such as leukemia and lymphoma), and molecular pathology reports (which present results from genetic and molecular tests performed on tumor tissue). Articles explaining each of these report types in more detail are available in this section.
What is cytology?
Cytology is the branch of pathology that focuses on the study of individual cells. Rather than examining an intact piece of tissue — in which the relationship between cells and the structures they form can be seen — a cytology examination looks at cells that have been collected on their own, either by scraping a surface, drawing cells into a needle, or spinning a fluid sample to concentrate the cells it contains.
Because individual cells are smaller and easier to prepare than tissue fragments, cytology samples can often be processed and reported quickly. The trade-off is that a cytology examination gives the pathologist less structural information than a tissue biopsy does. This is why cytology results sometimes lead to a recommendation for follow-up tissue sampling — not because the cytology result was wrong, but because a tissue sample can provide additional detail that a cytology sample cannot.
How is a cytology report structured?
Although cytology reports vary by laboratory and report type, most follow the same general structure as other pathology reports. Understanding the layout can help you find the information most relevant to your situation:
- Patient and specimen information — Identifies you by name, date of birth, and medical record number, and records the date the sample was collected, the type of specimen, and the body site sampled.
- Clinical history — A brief summary of background information provided by your doctor, such as the reason the test was ordered, relevant symptoms, or prior test results. This context helps the pathologist interpret the findings.
- Specimen adequacy — Many cytology reports — particularly Pap tests and fine-needle aspirations — include a statement about whether the sample contained sufficient well-preserved cells to allow a reliable assessment. A sample described as satisfactory or adequate can be interpreted with confidence. A sample described as unsatisfactory or non-diagnostic did not yield enough usable cells, and the test will need to be repeated.
- Diagnosis or result category — The most important part of the report. This states the pathologist’s conclusion — either as a specific diagnosis or as a result category within a standardized reporting system (see below). This is the section your doctor will focus on when discussing your results.
- Descriptive comments or microscopic findings — Some cytology reports include additional observations about the cells examined, such as specific abnormal features noted or incidental findings unrelated to the primary question. This section provides context for the diagnosis but is usually not essential for understanding the main result.
- Recommendations — Some reports, particularly those using standardized reporting systems, include guidance on suggested follow-up based on the result category — for example, recommending repeat testing, colposcopy, or a tissue biopsy.
How is a cytology sample collected?
The method of collection depends on the part of the body being sampled. The most common types of cytology procedures include:
- Pap test (cervical or anal cytology) — A small brush or spatula is used to collect cells from the surface of the cervix or anal canal. The cells are either spread directly onto a glass slide or rinsed into a liquid preservative (liquid-based cytology). Pap tests are used to screen for precancerous changes and cancer.
- Fine needle aspiration biopsy (FNAB) — A thin needle is inserted into a lump, lymph node, or organ, and suction is applied to draw cells into the needle. Fine-needle aspiration biopsies are commonly performed on thyroid nodules, salivary gland masses, lymph nodes, breast lumps, and lung nodules, often guided by ultrasound or CT imaging.
- Sputum cytology — Cells coughed up from the airways are collected in a sputum sample and examined. This is occasionally used to investigate lung abnormalities.
- Urine cytology — Cells shed from the lining of the urinary tract are collected in a urine sample and examined. Urine cytology is used to detect cancer cells in the bladder or upper urinary tract.
- Fluid cytology (effusion cytology) — Fluid that has accumulated in body cavities — such as the space around the lungs (pleural fluid), around the heart (pericardial fluid), or in the abdomen (ascites) — is sampled with a needle, and the cells within it are examined. Finding cancer cells in these fluids usually indicates that cancer has spread to the lining of the body cavity.
- Brushing or washing cytology — During procedures such as bronchoscopy (examination of the airways) or endoscopy (examination of the digestive tract), a small brush may be passed across an abnormal area to collect surface cells, or a small volume of fluid may be flushed over the area and collected. These samples are processed in the same way as other cytology specimens.
How is a cytology report different from a tissue pathology report?
A standard tissue pathology report — the type produced after a biopsy or surgery — describes what the pathologist saw in an intact piece of tissue, including the architecture (the way cells are arranged and organized) as well as the features of individual cells. Because tissue architecture carries important diagnostic information, tissue biopsies generally allow for more precise diagnoses than cytology samples.
A cytology report describes the features of individual cells collected without their surrounding tissue context. Because the pathologist has less information, cytology reports often use a different set of result categories that reflect this uncertainty. Instead of stating a definitive diagnosis, many cytology reports place results into one of several diagnostic tiers that describe the level of concern for disease, from clearly normal to highly suspicious or positive for cancer.
The specific categories used depend on the organ and the reporting system applied. Most organ systems now have standardized reporting systems with defined categories. The most widely used examples include:
- The Bethesda System — Used for cervical cytology (Pap tests). Categories range from Negative for Intraepithelial Lesion or Malignancy (NILM) at one end to positive for squamous cell carcinoma at the other, with intermediate categories such as ASC-US, LSIL, ASC-H, and HSIL describing increasing levels of concern for precancerous change.
- The Bethesda System for Thyroid Cytopathology — Used for thyroid fine needle aspirations. Six categories range from non-diagnostic (Category I) to malignant (Category VI), with intermediate categories that carry defined risks of malignancy and guide clinical decisions about follow-up or surgery.
- The Paris System — Used for urine cytology. Categories describe the likelihood that urothelial (bladder lining) cancer cells are present.
- The Milan System — Used for salivary gland fine needle aspirations.
Not all cytology reports use a formal tiered system — some are written as narrative descriptions — but the general principle of communicating a level of concern rather than an absolute diagnosis applies broadly to cytology reporting.
What do the common result terms mean?
Regardless of the organ system or reporting system used, certain terms appear frequently in cytology reports. Understanding what they mean can help you read your result more confidently:
- Negative for malignancy / benign — No cancer cells were identified. The sample appears normal or shows non-cancerous changes. This is a reassuring result, though it does not completely rule out cancer if clinical concern remains, because cytology samples sometimes fail to capture abnormal cells present elsewhere.
- Atypical cells / cytologic atypia — The cells show some abnormal features, but not enough to diagnose a precancerous condition or cancer. Atypical results are common and often reflect reactive or inflammatory changes rather than cancer. Follow-up testing is usually recommended to clarify the finding.
- Suspicious for malignancy — The cells have features that raise strong concern for cancer, but the sample does not have enough cells, or the abnormal features are not quite definitive enough, to make a certain diagnosis. A tissue biopsy is almost always recommended after a result in this category.
- Positive for malignancy — Cancer cells are present. This is a definitive result indicating that cancer has been identified in the sample. Further tissue sampling may still be needed to fully characterize the cancer before treatment can be planned.
- Non-diagnostic / unsatisfactory — The sample did not contain enough cells, or the cells were too poorly preserved, to allow the pathologist to make any assessment. A non-diagnostic result does not mean the result is normal — it means the sample needs to be repeated.
Can a cytology result give a definitive diagnosis?
In some situations, yes. A cytology result that is positive for malignancy is a reliable indicator that cancer is present, and in many clinical settings — particularly for thyroid nodules, cervical abnormalities, and effusion fluids — cytology results directly guide management decisions.
However, cytology results have limitations that tissue biopsies do not. Because individual cells are examined without their surrounding tissue context, cytology cannot always determine exactly what type of cancer is present, how deeply it has grown, or whether it has spread. For these reasons, a tissue biopsy is often recommended after a cytology result that is suspicious or positive, particularly when information from the tissue is needed to plan surgery or other treatment.
It is also worth understanding that a negative cytology result — while reassuring — does not always mean cancer is absent. False-negative results can occur if the abnormal cells were not captured in the sample. When clinical suspicion for cancer remains high despite a negative cytology result, your doctor may recommend repeat sampling or a tissue biopsy.
What happens after a cytology result?
What happens next depends on the result category, the organ involved, and your clinical situation. General patterns include:
- Negative or benign results typically lead to routine follow-up or continued screening at regular intervals, depending on the context.
- Atypical results usually prompt repeat cytology or a tissue biopsy, depending on the degree of atypia and the organ involved.
- Suspicious results almost always lead to a tissue biopsy to obtain a more definitive diagnosis before treatment decisions are made.
- Positive for malignancy results typically lead directly to further workup — additional tissue sampling, imaging, and referral to the appropriate specialist — to plan treatment.
- Non-diagnostic results are repeated whenever possible, using the same or a different sampling method.
Your doctor will explain what your specific cytology result means and what the recommended next steps are for your situation.
Questions to ask your doctor
- What type of cytology procedure was performed, and what part of my body was sampled?
- Which reporting system was used for my cytology result, and what does my result category mean?
- Does my result indicate that cancer is present, or does it describe a level of concern that requires further testing?
- If my result is atypical or suspicious, what is the estimated risk that cancer will be found on follow-up?
- Is a tissue biopsy recommended based on my cytology result, and if so, what type of biopsy?
- Could my cytology sample have missed cancer cells even if the result came back negative?
- If my result was non-diagnostic, what does that mean and when should the procedure be repeated?
- Are there additional tests — imaging, molecular testing, or other laboratory tests — that should be done alongside my cytology result?
- How long will it take to receive any follow-up biopsy or test results?
- Who will contact me with my results, and what is the best way to reach you if I have more questions?