Biopsy — Purpose, Procedure & Normal Values | MyMedicPlus

A biopsy is a medical procedure in which a small sample of tissue or cells is removed from the body and examined under a microscope by a pathologist to detect and characterise disease. It is the gold standard and definitive diagnostic tool for cancer, providing information on cell type, histological grade, receptor status (oestrogen receptor, HER2), and molecular markers that guide targeted therapy selection. Major biopsy modalities include fine-needle aspiration (FNA), core needle biopsy (spring-loaded or vacuum-assisted), punch biopsy for skin lesions, incisional biopsy (partial tissue removal), excisional biopsy (complete lesion removal), bone marrow trephine biopsy, and endoscopic biopsy using forceps through a gastroscope or colonoscope. Biopsies are performed by radiologists, surgeons, gastroenterologists, dermatologists, and oncologists — often using ultrasound, CT, or MRI guidance to maximise sampling accuracy and minimise complications. The procedure forms the cornerstone of oncological workup, inflammatory disease confirmation, and transplant organ assessment.

Biopsies are ordered whenever imaging findings, clinical examination, or laboratory results reveal a suspicious abnormality that cannot be definitively characterised without microscopic tissue analysis. Common indications include evaluation of a breast lump or mammographic microcalcifications, a solitary pulmonary nodule on chest CT, a suspicious skin lesion (to distinguish melanoma from benign naevus, basal cell from squamous cell carcinoma), cervical biopsy following abnormal colposcopy, lymph node enlargement of unknown origin, liver lesion characterisation, kidney or adrenal mass, elevated PSA with prostate cancer suspicion, thyroid nodule with high ultrasound risk features, gastric or colorectal polyp removal and assessment, and tissue confirmation of inflammatory or autoimmune conditions such as Crohn's disease, coeliac disease with villous atrophy, autoimmune hepatitis, and vasculitis.

Preparation varies by biopsy type. For superficial fine-needle or core needle biopsies, fasting is generally not required. For CT-guided deep organ biopsies, transbronchial lung biopsies, or surgical excisional biopsies performed under sedation or general anaesthesia, fast for 6–8 hours beforehand. Stop anticoagulant and antiplatelet agents according to your doctor's individualised schedule: warfarin is typically stopped 5 days prior; direct oral anticoagulants (rivaroxaban, apixaban) 24–48 hours; clopidogrel 5–7 days. Aspirin may be continued for core needle biopsies but held for surgical procedures. Inform your clinical team of all current medications, any known allergy to local anaesthetic (lidocaine), and any bleeding disorder including haemophilia or thrombocytopaenia. Arrange transport home if sedation is planned. Wear comfortable, loose-fitting clothing, and avoid vigorous exercise or heavy lifting on the day of the procedure.

The skin over the biopsy site is cleaned with antiseptic solution and local anaesthetic (lidocaine 1–2%) is injected into the skin and subcutaneous tissue — you will feel a brief sting followed by pressure but not sharp pain once the anaesthetic takes effect. For a core needle biopsy, a hollow spring-loaded or vacuum-assisted needle is advanced through the anaesthetised tissue into the target lesion; it retrieves a cylindrical tissue core approximately 1–2 mm in diameter and 15–20 mm in length. Two to five passes are typically made to obtain adequate tissue. Ultrasound or CT guidance is used for lesions in the breast, liver, kidney, lung, or lymph nodes. For skin punch biopsy, a circular blade 3–6 mm in diameter removes a disc of full-thickness skin. For an endoscopic biopsy, small forceps passed through the working channel of the endoscope grasp and detach mucosal tissue fragments. All samples are immediately placed in formalin fixative and transported to the pathology laboratory for processing, staining, and microscopic examination.

Pathology results use standardised terminology. Reports classify findings as: benign (no malignant features, e.g., lipoma, fibroadenoma, reactive lymph node); atypical or indeterminate (requires further sampling or clinical correlation); pre-malignant (e.g., high-grade intraepithelial neoplasia, carcinoma in situ, Barrett's oesophagus with dysplasia); or malignant (cancer — specifying the primary cell type such as adenocarcinoma, squamous cell carcinoma, small cell carcinoma, or lymphoma). For confirmed cancers, the report includes histological grade (Grade 1 — well differentiated, Grade 2 — moderately differentiated, Grade 3 — poorly differentiated), mitotic rate per 10 high-power fields, surgical margin status (clear, close, or involved), lymphovascular invasion, and hormone receptor or molecular marker status (oestrogen receptor, progesterone receptor, HER2 for breast cancer; EGFR, ALK, PD-L1 for lung cancer). Immunohistochemistry panels identify tumour lineage markers. Routine histology results are available in 5–10 business days. Molecular profiling and next-generation sequencing panels may require 2–4 additional weeks. Your oncologist, surgeon, or specialist will discuss findings and formulate a multidisciplinary treatment plan.

Common minor side effects include bruising, bleeding, and soreness at the biopsy site for 1–3 days, managed with paracetamol. Infection at the biopsy site occurs in fewer than 1% of procedures when aseptic technique is maintained. Organ-specific risks include pneumothorax for lung biopsies (2–5% rate, most resolve without treatment), haemorrhage for liver or renal biopsies (~1%), and haematoma formation. Tumour seeding along the needle tract is extremely rare, estimated at fewer than 1 in 20,000 procedures for most solid cancers. Bone marrow biopsy causes aching posterior iliac crest pain lasting 1–2 days, usually manageable with analgesia. A sampling error (false-negative result) occurs when the needle misses the target lesion, most often in lesions smaller than 10 mm — imaging guidance reduces this risk to approximately 5–10%. An inconclusive or non-diagnostic biopsy may require repeat sampling or open surgical excision. A biopsy alone cannot always identify the primary cancer site; comprehensive immunohistochemistry and molecular profiling panels are needed when the primary origin is unclear.