Clinical Chemistry

Clinical Chemistry input is critical to all aspects of the patient care pathway, including screening, diagnosis and monitoring of many conditions. We process between 5,000 and 6,000 samples per day and receive 6 to 7 million test requests per year. These samples come from:

• Newborns to elderly patients
• Acutely ill patients on the Neonatal Unit (NNU), the Critical Care Unit and the Emergency Department (ED)
• Patients at outpatient clinics including Oncology and Renal Dialysis
• General Practice (GP) clinics
• Research and Clinical Trials

Opening times

• Monday to Friday: 08:00 to 20:00.
• Saturday: 09:00 to 16:30*

*The Saturday/Sunday/Bank Holiday service offered by all departments is intended for essential work.

Note: Specialist tests are not performed at weekends.
The exceptions are:

• CSF Xanthochromia samples will be analysed Mon-Fri 9am-5.30pm, and Sat-Sun+ Bank Holidays 9am-4pm. Outside of these hours samples will only be analysed after discussion with the on-call Consultant Biochemist, or be left to the next morning.
• Porphobilinogen (PBG) samples will be analysed within 24 hours if received Sun-Fri. Samples received Friday afternoon or anytime Saturday will be analysed on Sunday only after discussion with the on-call consultant biochemist, or will be left until Monday.

Out of Hours

Urgent work will be processed at any time. The Biomedical Scientist (BMS) on call for each department may be contacted through the RCHT Hospital switchboard (01872 250000).

Type of samples we handle

Respective add on testing

Specimens are retained in Clinical Chemistry under appropriate storage for up to 3 days. It is possible to ask for tests to be added to samples already received provided the analyte required is sufficiently stable. It may not be possible to add certain tests which are known to deteriorate after a short time e.g. Troponin may only be added within 24 hours of obtaining the sample.
Troponin must be tested within 8 hours.

When an add-on test has been requested but testing not possible this will be reported. Within RCH the original MAXIMs form should be printed (do NOT create a new MAXIMs request), the add-on test hand written on and the form sent to the laboratory. Other locations can phone the Clinical Chemistry office.

The Automated Laboratory & STAT Area

The Automated Laboratory handles all our hospital, outpatient and GP work, and is therefore responsible for producing the majority of Clinical Chemistry results. The STAT area within it is where urgent samples are prioritised and quickly processed so results are available within one hour. Also the very small samples we receive on babies from NNU and children are also handled here as they require extra care to maximise testing from the small samples.

Routine tests include:

• Renal, liver or bone function
• Hormones (Thyroid, Testosterone, LH, FSH, Progesterone, Prolactin)
• Haematinics (Ferritin, Folate and Vitamin B12)
• Blood Gases

Specialist tests include:

• hsTnT
• NT-proBNP
• Oestradiol
• Tumour markers (CA125, CEA, AFP, HCG)
• Alcohol
• Drugs (e.g. Digoxin, Lithium, Phenytoin) and Antibiotics (e.g.Gentamicin, Vancomycin)

Manual Laboratory/Specialist Techniques

As the name suggests any test performed here requires more laboratory staff input and specialist methods. These include:

• Ion Exchange Chromatography: HbA1c
• ELISA: Faecal Calprotectin & Faecal Elastase
• Spectrophotometry: CSF samples
• High Performance Liquid Chromatography (HPLC): 24hr Urinary Metanephrines – 24hr Urinary 5HIAA
• Chloride Meter: Chloride in sweat samples

We also send samples to other NHS laboratories for any specialist tests that we are unable to perform locally.

Behind The Scenes – Computer Algorithms

As well as testing patient samples, we can take results and further process them via our Pathology computer to extract more information that can be used in patient care.

Acute Kidney Injury (AKI)

AKI reporting is part of a national campaign to reduce short-term and long-term complications from deterioration in renal function, including death.

eGFR (estimated Glomerular Function) and Chronic Kidney Disease (CKD)

Using the eGFR the patient is then categorised as per national guidelines into a CKD stage, which the GPs particularly use in the management of their patients.

ASSIST-CKD (A programme to Spread eGFR graph Surveillance for the early Identification, Support and Treatment of people with progressive Chronic Kidney Disease.)

The Clinical Chemistry laboratory at RCH was the first in the country to initiate this quality improvement program. The Clinical Biochemists look at 5years of eGFR results and flag patients that potentially in the future will require dialysis. Reporting aims to either prevent the need for dialysis, delay the time to start dialysis and to provide adequate time to allow for patient preparation for dialysis or transplantation.