Reasons for ordering laboratory tests and relationship with frequency of abnormal results

Paul H H Houben, Ron A G Winkens, Trudy van der Weijden, Renee C R M Vossen, André J M Naus, Richard P T M Grol
Scandinavian Journal of Primary Health Care 2010, 28 (1): 18-23

OBJECTIVE: Laboratory tests are ordered on a daily basis, even though disease probability is often very low. Abnormal results, especially mildly abnormal results, can be difficult to interpret in these circumstances. Further insights into the occurrence of abnormalities can help improve rational test ordering and test interpretation. The objective was therefore to examine the frequency of mildly and markedly abnormal results and their relationship with physicians' reasons for ordering tests.

DESIGN: Prospective study. Participants. A total of 87 primary care physicians in the Netherlands collected data on 1775 patients.

MAIN OUTCOME MEASURES: The physicians recorded the reason for ordering the tests, the most probable diagnosis and the pretest probability. The laboratories' reference values and specified "action limits" were used to assess the number of abnormal results and markedly abnormal results, respectively.

RESULTS: Laboratory results were received for 1621 patients and 15,603 tests were reported (mean 9.6). The proportion of abnormal test results increased with increasing pretest probability (from 13.9% to 34.7%) and was 13.4% for tests ordered to reassure the patient and 13.3% for psychosocial diagnoses. The proportion of patients with at least one abnormal test result was high: 53.1% for tests ordered to reassure and 57.7% in patients with low pretest probability. Corresponding values for a marked abnormality were 11.1% and 12.4%, respectively.

CONCLUSION: Abnormal laboratory test results were frequent, even when pretest probability was low. Physicians should therefore carefully consider when tests are necessary. Future research could explore physicians' interpretation of test results and its impact on diagnosis and management.

Full Text Links

Find Full Text Links for this Article


You are not logged in. Sign Up or Log In to join the discussion.

Related Papers

Remove bar
Read by QxMD icon Read

Save your favorite articles in one place with a free QxMD account.


Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"