The Institute of Biomedical Science

All about clinical chemistry: the work and roles of clinical chemistry

What is clinical chemistry?

Chemical chemistry (also known as clinical biochemistry or chemical pathology) is the study of chemical and biochemical mechanisms of the body in relation to disease, mostly through the analysis of body fluids such as blood or urine.

In many diseases there are significant changes in the chemical composition of body fluids such as the raised blood enzymes due to their release from heart muscles after a heart attack; or a raised blood sugar in diabetes mellitus due to lack of insulin. Tests are designed to detect these changes qualitatively or quantitatively compared to results from healthy people.

Clinical chemists use a wide range of analytical techniques for example, molecular diagnostics, measurement of enzyme activities, spectrophotometry, electrophoresis, the separation of molecules based on physical characteristics and immunoassays The work involves manual techniques for which the biomedical scientist develops complex practical and interpretive skills, through to operation and management of highly automated testing systems capable of producing thousands of results an hour. All assays that are closely monitored and quality controlled.

Tests that require examination and measurement of the cells of blood, as well as blood clotting studies, are not included as these are usually grouped under haematology.

Typical roles

A clinical chemistry department within a hospital provides a link between front line clinical staff and the basic sciences employing analytical and interpretative skills to aid the clinician in the prevention, diagnosis and treatment of disease.

Diseases such as heart attacks, kidney failure, viral and bacterial infection, infertility, diabetics, high cholesterol, thyroid problems or measuring drug levels to make sure people are on the best dose are some of the many areas where the Clinical Chemistry Laboratory becomes involved in a persons. Some regional laboratories are involved in screening services such as phenylketonuria and cystic fibrosis in newborn babies, genetic screening and screening for illegal drug use.

A Day in the Life of a Biomedical Scientist in Biochemistry

Name: Simon Andrews
Works at: Biochemistry department, St Peters and Ashford Hospital
Career: graduated with a BSc degree in biomedical science from the University of East London (accredited by the IBMS).

It’s 8 p.m. on Sunday night and I’ve just taken over from my colleague who had a busy day and was very pleased to see me!

For the next 12 hours I shall be the on-call biomedical scientist for the department of Biochemistry at St. Peter’s Hospital, Ashford performing diagnostic blood tests on urgent samples taken from those patients who are in need of urgent medical attention. I expect to receive samples from the Accident and Emergency Department (A/E), from ITU, the Special Care Baby Unit, the Maternity Unit, the children’s’ wards and from everywhere else in the hospital.

The first thing to do is to make checks on the huge automated analysers that are interfaced to the pathology computer. I’m running the quality controls now, which must produce results within strict ranges before I can analyse any patients’ blood tests. I’ll be making absolutely sure that the analysers are producing accurate results and that everything is documented.

My bleep has just gone off telling me to phone A/E about some bloods are coming down the air-chute syste, they are from a 2 year old with a rash and possible meningitis. I make my way along the corridor to the Pathology Reception, where samples are received and prepared, to look for the samples, and make a mental note that some time tonight they are quite likely to decide to take some cerebrospinal fluid for analysis from this patient.

I start work on this tiny blood sample, carefully separating the serum from the blood cells, and before too long it is on the analyser and I can dash back to pick up the rest of the samples which are now arriving in quick succession.

The bleep has been going crazy and there’s lot to do – a road traffic accident patient has been brought into A/E. They don’t know his name so have given him a special emergency ID with a special red ID number. Results are needed fast and they have also been talking to the on-call transfusion specialist. We are working together swiftly handling these urgent samples, checking them carefully, giving them a unique computer ID, entering data onto the computer which will interface with the analysers in both our departments. And then finally we are away back to our laboratories.

These bloods go on next and the baby’s results are now ready. I check them, then transmit them so that they are available on the main hospital computer. I phone doctor who needs to know these straight away as there is one particular result that indicates an infection which could be meningitis.

I go back to reception now where there are more bloods waiting, including one from ITU - a post operative patient being closely monitored, one from a septic pre-term baby on Special Care, one from a cardiac patient on the assessment unit and another from a collapsed elderly lady on A/E. The bleep goes again! There’s a baby in Resus A/E with acute asthma and epileptic fit. It’s quite a batch forming now but that’s fine, I’ll be able to put them all on together.

I’ll check those results on the RTA now – they don’t look too bad but phone them through to A/E anyway and ask if there is any news about the patient’s name yet.

Well now it’s 5.00 a.m. and it’s become a bit quieter. I’ve had 37 urgent samples so far tonight, and, yes, I did get a CSF from the first baby and it was treated for meningitis.

I have some checks to make on the analysers and some maintenance measures that keep them in good working order, so it’s a bit of TLC for the next hour. There are strict safety measures too in the laboratory so it’s a case of decontamination for some of the equipment and workstations. This quiet time is also good for making checks on the work lists for each work section so that we keep completely up to date with all of the requested tests to ensure that nothing has been overlooked during the day. There are several areas of different kinds of work in biochemistry with both automated and manual tests using many kinds of analytical equipment. We also have a commitment to Continuous Professional Development so there is always something to catch up on with planning of training and appraisal.

It’s about 6 o’clock now so I’m expecting lots of samples to arrive from those in-patients who are the most unwell and need the closest monitoring, namely those in ITU, SCBU, High Dependency Unit, and the Cardiac Care unit. Other urgent samples continue to arrive randomly.

8 o’clock arrives and I’m delighted to hand over to the next on-call colleague, and especially delighted to hand over the bleep!

Our thanks to Judith Gallagher at the pathology department at Ashford's and St Peter's Hospitals and the IBMS's Clinical Chemistry Advisory Panel.