Laboratory examination in primary care is often used to monitor patients with known diseases. Furthermore, it is applied for screening patients, since the differential diagnosis in primary care is often not very specific. Diseases are excluded rather than confirmed in most cases. The LESA-initiative (Landelijke Eerstelijns Samenwerkings Afspraken; Dutch cooperative agreement in primary care)¹ with the updated national model of the “problem-oriented request form” for laboratory research has contributed to a more rational use of laboratory testing. When laboratory examination is applied for screening purposes, abnormal results can be found that may indicate some unexpected pathology. Recognition and interpretation of abnormal results by the laboratory specialist may be helpful for general practitioners. The laboratory specialist can interpret abnormal test results and determine whether additional tests are needed. In most cases comments are added to the report. This way of consultation is called reflective testing.

The fact that the laboratory specialist takes the initiative to add tests to an original request form of the general practitioner, is not very common in the Netherlands (unlike in some other countries). Nevertheless, this procedure could improve the diagnostic process. For example, adding measurement of haptoglobin in case of a slightly increased (unconjugated) bilirubin could exclude possible hemolysis. The laboratory specialist can inform the general practitioner about the possibility of Gilbert’s syndrome (benign hyperbilirubinemia); a clinically insignificant congenital elevated conjugated bilirubin. Further examination or treatment is not necessary. In such cases it is obvious that the laboratory specialist initiates the additional testing, since he/she observes the abnormal test results and understands the potential consequences. Moreover, additional tests can be performed using the blood sample that is already present in the laboratory. The patient does not have to be sent in for a new blood sample and the diagnostic process can be finished in a shorter period of time.

Adding tests can sometimes be included into automated procedures (reflex testing). However, in cases with multiple disorders simultaneously it is difficult to enfold additional testing into an automated protocol. Considering adding tests (or not) is not a simple process, but requires professional, medical knowledge to assess the desirability of additional and appropriate tests. Previous test results and additional patient data – ideally available via an electronic patient record – are usually needed to achieve a proper assessment. An automated filter will be necessary in most cases to select those test results that are suitable for assessment by the laboratory specialist^2,3. Although the laboratory specialist is still dependent on the limited information on the request form of the general practitioner, the ongoing development of the electronic patient record will allow proper assessment of the clinical status of the patient.

Reflective testing⁴ is a procedure in which the laboratory specialist evaluates abnormal test results and decides whether additional tests are needed. This procedure is different from reflex testing (also called protocol testing), in which a predetermined test protocol is automatically completed. In laboratories in the United Kingdom reflective testing is seen as an integral part of consultation and essential for accreditation of the quality of the laboratory^5,6.

In June 2006, the Laboratory of Clinical Chemistry and Hematology of the Atrium Medical Centre in Heerlen, the Netherlands, introduced the procedure of reflective testing to local general practitioners. We examined in which kind of cases this way of support was appreciated by the general practitioners. A year after the start of the service we studied in what way our service influenced the policy of the general practitioners (in terms of diagnostics, treatment, referral).

The study showed that in the majority of cases, e.g. anemia, lipid spectrum, liver enzymes, reflective testing is appreciated. In some cases, adding tests by the laboratory without prior notification is less appreciated, e.g. troponin or PSA. Reporting only the test result, which is daily routine for most laboratories, is indicated as the least favourable of different alternatives (contacting the general practitioner by phone, adding comments to the report (without adding tests))⁷. These results are comparable with a recent study in the United Kingdom and support the external validity of the present study in the Eastern South of Limburg, the Netherlands. Other studies further support that adding comments by the laboratory is appreciated by general practitioners^8-10. The procedure of reflective testing is also appreciated by patients from primary care; 90% of the patients indicated to prefer additional testing by the laboratory before prior consultation of the general practitioner¹¹.

In the second part of our study we have demonstrated that reflective testing is found to be useful by the responding general practitioners in 99% of the cases⁷. In 53% of the cases reflective testing has had an active effect on the policy of the general practitioners, in terms of further diagnostics, (change of) medication or referral to a specialist. Taking into account the high response of the general practitioners (87%), we concluded that reflective testing is being experienced as useful by a vast majority of the local general practitioners. In a subsequent randomised clinical trial we are examining the effectiveness of reflective testing in primary care¹².

An important aspect of additional testing that needs to be studied is the cost effectiveness. Adding tests to an existing order is usually cheaper than a second blood sampling. The additional costs of the laboratory have to be compared with the profit for the patient when a diagnosis is established earlier, and the economic profit when a targeted treatment is started earlier or an unnecessary treatment is stopped. Reflective testing concerns only a small selection of patients. From our own database it has been shown that in 20% of the reports abnormal test results are observed, that need evaluation of the laboratory specialist. In 2-4% of the reports indeed additional tests and/or comments are added.

In conclusion, to our experience general practitioners generally appreciate extra support from the laboratory by means of reflective testing. They consider this service as useful and in 53% of the cases this has resulted in subsequent diagnostic testing, (change of) treatment or referral to a specialist. These results are similar to results from other laboratories.