Requesting of investigations

Specimen acceptance policy for Paediatric Histopathology in accordance with the Division of Laboratory Medicine (DLM) guidelines for specimen acceptance must be followed to ensure that all samples are correctly and unambiguously identified.

Clinical governance issues may arise from errors in specimen identification and/or insufficient clinical information being given with a specimen. To ensure that specimens are linked to the correct patient, adequate identifiers are essential.

All urgent and specimens on a cancer tracking pathway (HSC205) should be clearly labelled as such. The date and time the specimen was taken is important information that should be included on all requests to determine the length of fixation of the tissue specimen.

Specimen Acceptance Policy

All samples sent to Paediatric Histopathology must comply with our specimen acceptance requirements.

• All test requests ordered on the HIVE Electronic Patient Record (EPR) system must have a request form print out submitted with the sample.
• For non- HIVE requests or paper requests raised during HIVE down time see acceptance criteria below.

The following mandatory information must be provided for us to accept the specimen:

Essential Patient Identifiers:

• Surname
• Forename (not required in neonates if unknown)
• Unique identification number – MRN number, NHS and external hospital number for external cases
• Date of birth
• Address
• Gender

Essential Clinical Details:

• High risk status – to ensure health and safety of all staff
• Specimen site – must match on specimen pot and request card
• Relevant clinical information – to ensure all necessary investigations are performed
• Date/time taken – essential to ensure proper fixation of high risk specimens

Essential Sender Details:

• Ward/department – required for return of reports
• Consultant or GP – required for return of reports and contact in case of any errors/discrepancies
• Contact number/bleep – for frozen sections
• Name of person making request

Specimens that do not contain the required information or have discrepancies between the request card and specimen pot will not be processed in the laboratory until the necessary information has been obtained. The sender will be contacted to attend the laboratory to complete any missing information or correct any mistakes. The person correcting the patient or specimen details should be of appropriate seniority and able to take responsibility for the labelling of the specimen. This will result in a delay to specimen processing and reporting.

Consent for histological examination is not documented on the request forms but forms an integral part of the clinical process, for consent for the procedure.

Internal Paediatric Histology and placental requests are ordered on HIVE as ’Paediatric Histology’.

External Paediatric Histology request forms are available on request.

All Placental Histology requests must fulfil specific acceptance criteria and ranges / measurements specified where requested. New referral criteria was applied on 01.02.2023 as follows:

We will only accept the following placentas:

• Stillbirth (antepartum or intrapartum)
• Miscarriage (14+0–23+6 completed weeks’ gestation)
• Severe fetal distress defined as: pH <7.05 or base excess ≥ -12 or scalp lactate> 4.8mmol/l
• Preterm birth (less than 32+0 weeks’ gestation)
• Fetal growth restriction defined as: birthweight below 3rd centile or drop in fetal growth velocity of >2 quartiles or >50 percentiles
• Abnormal umbilical artery Dopplers (absent or reversed end diastolic flow)
• Fetal hydrops
• Early-onset (<32 weeks) Severe pre-eclampsia requiring Iatrogenic delivery
• Severe maternal sepsis requiring adult intensive care admission and/or fetal sepsis requiring ventilation or level 3 NICU admission
• Massive placental abruption with retroplacental clot.
• Baby for Post Mortem at RMCH

If the referral does not meet the criteria this will be discussed with the referring team and returned.

It is essential that gestation is specified and clinical details provided – without this we will be unable to accept the placenta.

Request forms

In accordance with the departmental and DLM Specimen Acceptance Policy, a minimum of four matching patient identifiers are required on the request form and the specimen pot before we can accept a sample. See specimen acceptance policy.

All external paper request forms should be completed in full (see above) and all information provided should be clearly legible. Any missing information or errors will result in a delay to specimen processing and reporting.

External Paediatric Histology request forms are available on request. External Request Form for Histological Examination of Placenta at RMCH: HIEXT2

Correct patient and specimen information is vital for us to provide a quality service to our users. Any specimens deemed to be high risk or potentially high risk should be clearly labelled as such to protect the health and safety of all staff.

If a patient is part of a research project, this should be clearly labelled on the request form to ensure that the specimen undergoes the correct agreed procedures.

HIVE requests

Specimen acceptance criteria for HIVE samples are identical to those for samples requested in the conventional manner. HIVE generates histology labels for both the requisition form and each sample pot. Please ensure the correct label is attached to the correct container. HIVE labels must be attached to the specimen container and not to the lid of the container.

Unlike some of the other pathology disciplines, Paediatric Histopathology still require a request form for all specimens requested on HIVE.

ALL SAMPLES FOR PAEDIATRIC HISTOLOGY MUST BE ORDERED ON HIVE USING PAEDIATRIC HISTOLOGY SELECTION AND NOT HISTOLOGY OR CYTOLOGY.

Storage of specimens

Prior to transport to the laboratory, it may be necessary to temporarily store specimens. All specimens that are placed into formalin should be kept at room temperature until transported to the laboratory. Specimens in formalin should not be placed in the fridge as this will have a negative impact on fixation and therefore preservation of the tissue.

All dry specimens and specimens in Zeus Fixative ideally should be transported to the laboratory immediately. Where this is not possible, these specimens should be stored in the fridge temporarily and transport should be arranged as soon as possible.

Transport of specimens

All specimens should be transported in the relevant fixative. All specimen pots should be tightly sealed and transported using specimen bags, where appropriate. The request card should be placed in the pocket of the specimen bag, and the pot inside the sealed bag to ensure the safety of all staff.

Specimens from theatres are delivered to our specimen reception throughout the day. These specimens should be recorded when delivered to maintain the necessary records.

Fixed samples arriving Outside of Laboratory working hours should be placed in the tray at specimen reception.

Fresh samples arriving outside of Laboratory working hours can be placed in the specimen reception fridge.

All specimens sent via Royal Mail/courier should be packaged according to the guidance available on the Royal Mail website. It is the responsibility of the sender to ensure that specimens are appropriately labelled and packaged.

NEVER USE THE PNEUMATIC TUBING SYSTEM

Specimen tracking

Many of our service users have systems in place to track specimens. If specimen acceptance criteria are applied at the time of tracked receipt, the specimen can be returned to the sender quickly should any discrepancy be identified.

Appropriate action in the event of a specimen acceptance failure involving fresh tissue (e.g. frozen section, gel sample) or an Urgent / HSC 205 sample is decided at the discretion of the reporting pathologist. The decision to accept and process pending confirmation may be taken by the reporting pathologist. It is the responsibility of the Pathologist to communicate this within the report.

Requesting formalin pots

Requests for Formalin pots will be dealt with as soon as is practicable, however if you require the pots urgently please inform the laboratory by telephone on 12240. Sufficient notice should be given.

Handling formalin

The department uses 10% neutral buffered Formalin (4% formaldehyde) and this should be handled with care at all times. We obtain our formalin from CellSolv, a reputable supplier and they have issued the following safety information:

10% Formalin

Acute Toxicity           Category 4 – Harmful if inhaled

Skin Sensitizer         Category 1 – May cause an allergic reaction

Carcinogen               Category – 1B May cause cancer

Mutagen                    Category 2 – Suspected of causing genetic defects

All solutions containing formalin are suspected carcinogens, mutagens and sensitisers. The solutions should be handled with care, minimising skin contact. Safety equipment including gloves should be worn and any spill on the skin should be washed as soon as possible. Contaminated clothing should be removed immediately and washed before re-use as the chemical can soak through clothing to stay in contact with the skin for a long period of time. Handle with care and avoid any situations which could potentially result in formalin spillage.

Formaldehyde vapours in the air are also harmful. The safety limit for formaldehyde in air is 2 part per million (2ppm). This means workers should not be exposed to formaldehyde vapour above this level (averaged over the period) for more than 15 minutes at a time. Testing machines are available to monitor the level of formaldehyde vapour in air but as a rough guide, 2ppm of formaldehyde will have a strong, unpleasant smell and will start to sting the nose and eyes on first entering the room. This check is only valid on first entering the room as the senses quickly acclimatise and will be less sensitive. In most hospitals with proper bench extraction it is unlikely that the limit will be reached in normal use but may be in the event of a spill.

Information from: Formalin Usage Guide for Hospitals – CellSolv Version 2 (Jan 2019) (external safety data sheet, contact laboratory if required)

Formalin may be disposed of down a sink suitable for clinical waste with copious amounts of running water in a well-ventilated room depending on local environmental rules. However, please check your local rules.

Formalin spillages

Formalin should be handled with care and sent in appropriately sized containers with secure lids to minimise the risk of a spillage. Specimen pots should be secured in a sealable plastic specimen bag.

Each sender who handles formalin should have their own policy or procedure and equipment for handling formalin and dealing with a spill, and should have sourced from a reputable supplier.  Spillages should be dealt with as soon as it safe to do so. Salvage of any specimen should be of the highest importance as it is likely to not be repeatable. Specimens must not be discarded.

The sender must inform the laboratory of any spillage where the specimen may have been lost, partially lost or its integrity compromised. This should be reported as an incident and the sending clinician should be informed as soon as possible.

Couriers and porters should not attempt to handle a formalin spillage in transit without having received proper training. In the event of a spillage please follow local spillage protocols. The Histology laboratory can be contacted for advice Mon-Fri 09:00-17:30 on 0161 701 2240.

Our formalin supplier, CellSolv, has issued the following guidance on spillages.

Spillage volumes:

• Minor spillages (up to 200ml) – usually can be dealt with by 1 or 2 staff using simple procedures
• Large spillages (200ml – 5 litres) – require the use of a formaldehyde spillage kit
• Major Spillages (over 5 litres) – should be dealt with by Fire Service

Dealing with minor spills

In a hospital environment formalin is mostly handled in very small containers with less than 100ml of 10% formalin solution. A spill of this size is unlikely to contaminate the air to dangerous levels if dealt with promptly. The spill can be wiped up with absorbent material by staff members wearing suitable impervious gloves such as nitrile gloves. The contaminated material should be sealed in plastic bags for disposal and removed from the room as soon as possible. It is important not to simply dispose of the contaminated material in an open bin as the formaldehyde will continue to contaminate the air.

Dealing with large spills

Some hospitals use formalin solutions in larger quantities, for example large specimen containers/buckets for whole organ fixing. A spill in this case can be up to ten litres and can cause more serious air contamination. Such a spill should only be tackled by trained personnel with appropriate personal protective equipment. This should include protective gloves, over-suit, boots and respiratory protective equipment (R.P.E.) with forced air feed or formaldehyde selective filters. The spill should be contained by absorbent booms and prevented from entering drains. The spill should then be absorbed into an appropriate absorbent medium, sealed in an airtight container and kept as special waste for professional disposal.

• Evacuate all staff from immediate area and nearby areas of spillage
• Wearing the appropriate personal protective equipment and full face mask, use a formaldehyde spill kit to contain the spillage
• Ensure all materials used to tackle the spillage are appropriately contained and disposed of

Dealing with major spills

• Evacuate the area
• Break nearest fire alarm point
• Phone emergency number for your department (e.g. 2222)
• Inform of nature and site of spillage

Dealing with Biological spills

• The Histology laboratory can be contacted for advice Mon-Fri 09:00-17:30 on 0161 701 2240.

(Last reviewed August 2024)