Specimen requirements

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The NSOPS service examines specimens either diagnostic or excisional, of any tissue from the eye or its adnexal structures. Specimens for cytological investigations are also accepted which include surface impression cytology and cytology of fluid such as tears, aqueous, vitreous, or fluid from cystic lesions.

Guidance on which specimens should be submitted for examination may be found at:

https://www.rcophth.ac.uk/wp-content/uploads/2016/07/Ocular-Pathology-July-2016.pdf

Some specimens may be referred to other departments/centres for expert opinion or for techniques not performed here such as PCR (on tissue sections), molecular studies, and impression cytology. See a list of our main referral centres.

The department does not arrange or provide any other pathology services e.g microbiology, or fresh virology samples. If these investigations are required, the requesting clinician must submit a separate specimen to an appropriate service.

It is not possible for this laboratory to split a specimen under sterile conditions.

High risk specimens/danger of infection

It is the responsibility of the requesting clinician to indicate on the request card if the patient is known or suspected to be within a “High Risk/Danger of Infection” category eg HIV, TB, Hepatitis B, Hepatitis C, (this list is not exhaustive)  to facilitate appropriate handling. These specimens need to be formalin fixed for a longer period of time to ensure the health and safety of the staff.

Frozen sections (including specimens for immunofluoresence) will NOT be carried out on high risk specimens.

Routine histopathology

Specimens for routine histopathology are required to be placed into 10% neutral buffered Formalin, which is available on request from the laboratory. Formalin is used to fix the specimen and preserve the tissue in as life-like state as possible. If there is a delay between the removal of the tissue and fixation in Formalin, this can adversely impact the specimen integrity and therefore report. NB: In cases where sebaceous carcinoma is suspected specimens should still be submitted in formalin.

The choice of methodology and appropriateness of the investigation are at the discretion of the consultant pathologist who is guided by details on the clinical request form and knowledge of laboratory methods and current “best practice”. Ophthalmologists are free to discuss the methods employed for any given specimen, but the final decision remains the remit of the Consultant Pathologist.

Fast paraffin processing

In urgent cases (often eyelid tumour surgery where a lesion is being excised, and subsequent reconstruction depends on knowledge of whether the margins are tumour free) a “fast paraffin” approach may be considered.

If the specimen can be delivered to the laboratory on the morning of the initial surgery, it can be processed overnight and an opinion will be available by midday on the next working day.

NB: This service is labour-intensive and must be booked in advance by contacting laboratory staff in advance to ensure both technical and clinical staff are available. This service is only available to MFT ophthalmologists.

Frozen sections

Unfixed histology specimens may be sent for frozen section if other forms of rapid diagnosis are not appropriate. This service is only available to MFT ophthalmologists.

Every attempt will be made to provide a frozen section service during working hours. Users are requested to adhere to the following requisites:

Requests for frozen sections should be booked 24 hours in advance wherever possible. Bookings can be made by contacting the Laboratory on 0161 276 8808.  Patient information, clinical information, Clinician’s name and the theatre number where the surgery will be taking place will be required at this time.

Frozen sections WILL NOT be undertaken on high-risk specimens. Such information MUST be disclosed to the Laboratory and included on the request card.

The sample MUST be accompanied by a completed request card which must clearly indicate the contact number and name of the person to whom the result is to be conveyed.

Before sending the sample ring 68808 to warn the laboratory it is on the way.

Samples for frozen sections should be transported to the Laboratory in an appropriately labelled dry pot and handed directly to the technical staff as quickly as possible and arrive by 4.30pm.

Immunofluoresence

Conjunctival biopsies for immunofluorescence  (e.g. samples querying Ocular Cicatricial Pemphigoid) should be placed directly into transport medium. It is extremely important these specimens are NOT placed in formalin as the technique cannot be carried out on fixed tissue.  The sample in transport medium should also be labelled with relevant patient identification details. Gel tubes are available from Adult Histopathology Specimen Reception 0161 276 8808.

These samples need to be sent to the laboratory as soon as possible.  If they cannot be sent by 5pm please ensure they are stored in a fridge and delivered first thing the next morning.

Immunofluorescence is not available on high risk specimens.

Cytology investigations

Cytology is the investigation of small samples of dispersed or dissociated cells and other tissue components devoid of natural tissue architecture.

Specimens for cytological investigations include surface impression cytology and cytology of fluid such as tears, aqueous, vitreous, or fluid from cystic lesions.

Cytological investigation provides a preliminary diagnostic impression and should not be regarded as providing a definitive diagnosis. If there is uncertainty about its use in a particular case, it is preferable to discuss the case with the consultant pathologist prior to obtaining the specimen.

Vitrectomy specimens: Please contact the laboratory prior to sending vitrectomy specimens. We prefer to receive a formal pars plana vitrectomy in a cassette or bag. If samples are required for microbiology, virology or PCR please remove these from the cassette/bag first. Samples from MFT should be sent fresh immediately to the laboratory. Fresh samples should be delivered by 2pm. Samples taken on a Friday afternoon can be fixed in an equal volume of 10% neutral buffered formalin. Samples from other hospitals sent by post should be fixed in an equal volume of 10% neutral buffered formalin.

Small volume cytology specimens: The syringe used in the collection of the sample may be submitted with the fluid inside. Needles must be removed and the syringe capped. MFT specimen should be sent fresh as soon as taken. Samples taken on a Friday afternoon should be fixed using an equal volume of 10% formalin drawn up into the same syringe. Indication should be made on the request form as to whether the specimen is fixed or not.

Please do not send unfixed specimens from outside hospitals unless by same day courier.

 

If microbiological investigation is required, the requesting clinician

must submit a separate specimen to an appropriate microbiology service.

It is not possible for this laboratory to split a specimen under sterile conditions.

Impression Cytology

These samples should be submitted in a pot containing formalin in a manner similar to histology specimens.  These samples are sent to the NSOPS service within the UCL Institute of Ophthalmology London.

 

(Last reviewed February 2019)