From dream to reality - pre-analytical quality improvement

Sverre Sandberg

The spotlight is on two increasingly important topics: patient safety and the uptake of total quality management practices in clinical laboratories.

‘The time for a European Conference on Pre-analytical Phase is now,’ says Scientific Committee Member Dr Sverre Sandberg, Head of the Laboratory of Clinical Biochemistry, Haukeland University Hospital, in Bergen, Norway and Chair of the Scientific Division in the European Federation of Clinical Chemistry and Laboratory Medicine . ‘While in the past a lot of efforts were expanded to improve the quality of analytical phase of laboratory practices, for example by the technical optimisation of test instruments, today it’s increasingly realised that about 70% of errors in laboratory diagnostics happen before the samples hit the analysers at all.’

Standardisation processes will play a big role at the Parma conference. Sources for errors lurk all around the lab department, from receipt up to final sample analysis. They range from wrong preparation to even a swapped specimen. Patient identification shows a big failure rate, but the actual figures can only be estimated. ‘Before the era of computerisation about 2-3 % of samples were mixed up. Manual work is simply fault-prone. But still, even with barcode systems and automated technologies, specimen interchange can happen if samples are not correctly tagged. Hence the only way to prevent confusion of patient samples is to have strict workflow routines.’
Another question occupying lab experts is how to acquire proper samples. Obtaining the basic state of samples before analysis is the basic requisite for correct testing results, so the correct transport of substances plays a key role. For example, wintry cold spells substances can inadvertently freeze during transport and thus falsify test results.

Furthermore, many errors in the pre-analytical phase originate at bedside, Prof. Sandberg emphasised: ‘One of the most important things is to request the correct analytes to a certain question. If physicians are not educated right and take the wrong kind of test, they will not obtain the answers they were looking for.’
Thus, education and interdisciplinary communication are most important in order to avoid test errors. Consequently Dr Sandberg and colleagues hold regular meetings with clinical colleagues to discuss what tests to perform for which indications and how to interpret the results correctly. The latter cannot be taken for granted, he points out. Although clinicians have broad knowledge in their subject, it is not clear if they are familiar with suitable testing procedures.

In Parma, Prof. Sandberg will lecture on The impact of biological variability on laboratory testing, to approach this problem. Biological variability occurs in ‘between subject variation’ as well as ‘within subject variation’. The first means, for example, that haemoglobin has different concentrations in different patient groups, depending on factors such as gender or age. This is well known and held on in reference intervals. The ‘within subject variation’ is a more complicated and crucial factor. It describes the variation of haemoglobin concentration in the blood of an individual patient. Some variation constituents depend on the season, or time of day, others are more individual and due to unknown causes This means that haemoglobin can vary between + / 5-10 % independent of the analytical imprecision. ‘It means that we first have to draw the physician’s attention to when would be the best point in time to perform the test, the best sample to take – for example capillary vs. venous samples – and then, after delivering test results to them, we must clarify what the variations in haemoglobin values in a patient really mean and what variations in test results can be expected from within-subject and analytical variation.’

Further details: www.preanalytical-phase.org
 

28.02.2011

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