OBJECTIVE: To determine the consistency among the practice guidelines of the Dutch College of General Practitioners with respect to the use of blood tests. METHODS: The authors evaluated 64 practice guidelines of the Dutch College of General Practitioners. For each guideline, they analyzed each sentence that contained a reference to a blood test to determine the clinical situation in which the test should be performed (the indication) and to determine the tests that should be performed in that situation (the recommended test). An incomplete recommendation refers to a guideline that mentioned a blood test but did not identify the indication for that test. An inconsistency refers to the situation in which one guideline recommended a certain test for a given indication whereas another guideline mentioned the same indication but did not recommend the same test. RESULTS: Twenty-seven practice guidelines mentioned blood tests. Of these, three explicitly recommended not to request blood tests. Five guidelines contained incomplete recommendations, and the authors encountered two inconsistencies among the guidelines. Twenty-three guidelines mentioned blood tests and allowed the authors to identify indications and recommended tests. CONCLUSION: The identification of indications and recommended tests allows evaluation of consistency among practice guidelines. Although some incomplete recommendations and inconsistencies were discovered, the majority of the guidelines provide clear and unambiguous recommendations for blood-test ordering in primary care.