Department of Histopathology
The Cellular and Anatomical Pathology Department within the Combined Laboratories at Derriford Hospital incorporates Histopathology, Cytopathology, Neuropathology, and Anatomical Pathology.
The department receives approximately 34,000 surgical biopsies, 2,000 non-cervical samples, and undertakes 1,100 postmortem examinations each year.
The laboratory performs a range of tests on tissue samples in order to determine the nature of a patient’s disease. A major part of the work involves the diagnosis of cancer and pre-cancerous conditions that enables doctors to give the best type of treatment to their patients. The majority of straight forward biopsies and resections (i.e. those not requiring additional tests) are reported within 7 working days, and fluid samples, within 3 working days.
Sending Biopsy and Resection Specimens to Histopathology and Neuropathology
All tissue samples are to be sent to the laboratory fixed in formalin, with the exception of:
- Frozen section cases for immediate diagnosis
- Ovarian and endometrial tumour resections
- Mastectomies and wide local excisions
- Skin or mucosal biopsies that require immunofluorescence (IMF)
- Liver biopsies for Dry Copper or Iron Weight analysis
- Skin biopsies for intraepidermal nerve fibre density
- Muscle and nerve biopsies
- Protocols for these samples and important imformation is given below.
Rejection and Acceptance Criteria
- Completed request form with relevant demographics and clinical details: Under the International Standard ISO 15189:2012 Requirements for quality and competence for medical laboratories fulfilment requires that the laboratory meets both the technical competence and management system standards that are necessary for it to consistently deliver technically valid results. All specimens must be clearly and unequivocally identified with a minimum of three of the key identifiers. Key identifiers must be correct and match the information given on the request form. ISO 15189:2012 also states that the request form must include the name or other unique identifier of clinician, healthcare provider, or other person legally authorised to request examinations or use medical information, together with the destination for the report. Any non-conformity in respect to this will lead to delay in the specimen pathway.
- Specimens for intraoperative diagnosis must ideally be booked at least 24 hours in advance and sent fresh with completed request form as detailed above, with a contact number for result. Frozen sections on patients with suspected tuberculosis will be rejected.
- Specimens for immunofluorescence (IMF); the laboratory must be notified in advance prior to sending and two samples sent, one in formalin and the other wrapped in saline soaked gauze, with completed request form as detailed above. Samples for IMF should ideally be received within an hour, however samples which are not received by the laboratory on the same day they were taken will be rejected as the delay is too significant and the result will be adversely affected.
- Specimens where there is a risk of infection from a category 3 or 4 pathogen must be labelled clearly as danger of infection and double bagged.
Health and Safety Aspects
- Disposal of formalin; prefilled containers that have expired and are no longer required must be brought to the department of Cellular and Anatomical Pathology on Level 4 for safe disposal.
- Please do not send formalin fixed specimens through the pneumatic tube system.
Factors Affecting Results and Uncertainty of Measurement
i) Fresh Specimens
- Refrigeration; dry specimens must be refrigerated and not left at room temperature to prevent autolysis prior to transportation to the laboratory.
- Time taken for transportation to the laboratory; all specimens must be transported to the laboratory as soon as possible.
- Tests will be performed on any samples that have deviated from the recommended guidelines given for transportation time, but the user must be aware that this may compromise the quality of the result.
ii) Formalin Fixed Specimens
- Unless otherwise directed, all other specimens should be placed immediately following excision into 10% neutral buffered formalin to allow them to “fix”.
- Size of specimen container; specimens must not be squeezed into containers which are too small as this compromises fixation and may adversely affect the final report.
- An adequate amount of fixative must be added must be at least 10 times greater in volume than that of the specimen.
- Squeezing of small biopsies must be avoided as this can cause cells to become distorted and rendered unidentifiable when examined microscopically.
Bacteriological Examination of Biopsy Specimens
If the biopsy requires bacteriological investigation (for example, a lymph node that may be infected with tuberculous) part of the biopsy should also be sent separately without fixative in an appropriate sterile container to the Microbiology laboratory with a Microbiology request form. The Cellular and Anatomical Pathology and Microbiology request forms should be clearly identified with the ‘Danger of Infection’ labels and double bagged if a high risk pathogen is suspected (see below).
Specimens intended for the Cellular and Anatomical Department that are suspected to be infected with tuberculosis must always be sent in formalin.
Sending high risk specimens
If the tissue is suspected of being infected with the any Class 3 or 4 pathogens including; Tuberculosis, Hepatitis B/C, or HIV, then the specimen should be placed in 10% neutral buffered formalin and both the specimen container and form clearly marked ‘Danger of Infection’ and the relevant clinical information provided. The specimen container should also be placed inside two plastic specimen bags for transportation. If the specimen is a fluid sample please contact the cytology laboratory (extn. 52242) before taking the sample, for advice on how to send it.
If there is a risk of CJD please contact neuropathology staff (ext 54408), prior to sending the sample. Also refer to Trustwide Policies and Procedures/Clinical Governance/Infection Control/ Policy 56: Prevention of Transmissible Spongiform Encephalopathies in the Healthcare Setting.
The sectioning of unfixed tissue suspected to be infected with Tuberculosis or CJD poses a risk of acquired infection to laboratory staff and we are therefore unable to perform frozen sections for intra-operative diagnoses, from these cases. The laboratory will accept specimens suspected to be infected with Hep B/C or HIV as urgent intra-operative specimens requiring frozen sections.
The Department regard the following to be Urgent Specimens that will be prioritised throughout the system.
- As directed by Clinicians ( i.e. ‘red spotted’ or ‘2WW’ request forms).
- All tru-cut biopsies.
- All bronchial and pleural biopsies.
- All biopsies in which a diagnosis of malignancy is strongly suspected, other than in skin tumours (with the exception of melanomas or where directed by the clinician) and cervical biopsies (except where directed by the clinician). Examples of words/initials used on request forms for these cases include malignant, new growth, NG, tumour, TURBT and MM.
- Temporal artery biopsies.
- Products of conception (POC) with suspected molar change
- Atypical pigmented skin lesions, such as dysplastic naevus.
- Requests where a date by which the report is required has been completed
IN ADDITION PATIENTS REFERRED UNDER THE 2 WEEK-WAIT SCHEME AND ALL PROSTATE BIOPSIES ARE PROCESSED WITH HIGH PRIORITY THROUGH THE LABORATORY.
We aim to comply with the following targets:
- Target 1 - 80% of urgent biopsies, 2 week wait cases and needle core biopsies reported within 7-10 days of receipt of the specimen.
- Target 2 – 80% of routine cases reported within 14 days of receipt of the specimen.
Requesting frozen sections for immediate diagnosis.
Wherever possible, 24 hours prior notice should be given to the laboratory. In the event of our laboratory not being notified, no guarantee can be given that the specimen will receive immediate microscopic examination, as a pathologist may not be available at the time of receipt.
The unfixed tissue should be sent to the laboratory by a special messenger. Frozen sections cannot be prepared from specimens known or suspected to be infected with the following pathogens: Tuberculosis or CJD.
Please note that we are no longer able to offer a frozen section service to count neutrophils in specimens from orthopaedic joint revision surgery. Recent local audit and international published data shows low sensitivity and negative predictive values suggesting the test does not rule out infection and negative results are likely to be misleading.
Gynaecological (ovarian) and breast specimens (mastectomies and wide local excisions)
Please note if the specimen is known or suspected to be infected with the following pathogens, Tuberculosis, Hepatitis B/C, HIV or any other pathogen from Classes 3 or 4 the specimen should be placed in 10% neutral buffered formalin and not sent dry. Otherwise follow this procedure.
Specimens should be placed in an appropriately sized dry container for transport to the laboratory.
During normal working hours (08.30 – 17.30 Monday to Friday): Please arrange for the specimen to be transported to the laboratory immediately. Please notify the Laboratory (Tel Ext: 52362) that a fresh specimen is being sent, stating the patient’s name, nature of specimen and theatre number.
Outside normal working hours (17.30 to 08.30 Monday to Friday): Please arrange for the specimen to be refrigerated overnight and transported to the laboratory at 08.30 the next day.
Weekend (Friday 17.30 until Monday 08.30 hours and Bank Holidays): Please place the specimens in a container and add a suitable amount of formalin.
PLEASE DO NOT OPEN OR DISSECT THE SPECIMEN IN ANY WAY. This will compromise the assessment of margins and extent of tumour infiltration.
Immunofluoresence (IMF) on skin and mucosal biopsies
Please note if the specimen is known or suspected to be infected with Tuberculosis or CJD, the specimen should be placed in 10% neutral buffered formalin and not sent dry. Otherwise follow the procedure below. (See ‘Sending High Risk Specimens’ for further details).
As for Frozen Section Protocol, but the case details including name of patient, sample type, consultant, source and approximate time of removal and delivery will be required at time of notification.
During transportation the sample must be kept moist by wrapping the biopsy in gauze moistened, but not wet, with normal saline. Any delay in transit may compromise the result.
The form must clearly indicate that the specimen requires immunofluorescence (IMF). Any formalin fixed specimen accompanying the IMF must be either delivered with the IMF specimen with the clinical details of both specimens on the one request form, or a reference must be made on each of the two forms.
Biopsies taken at sites other than Derriford Hospital must be transported urgently and directly to the Cellular and Anatomical Pathology Reception, Level 4, by taxi.
Liver biopsies for dry copper and iron weight
Specimens for dry copper or dry iron weight are required to be sent dry. Please do not place the specimen in formalin as this will invalidate the result.
Reviewed December 2018
This page will be updated March 2019