Laboratory test ordering at physician offices with and without on-site laboratories.
BACKGROUND
Physician self-referral, ordering a test or procedure or referring to a facility in which a physician has a financial interest, has been associated with increased utilization of health care services.


OBJECTIVE
To examine the association between on-site laboratories and laboratory test ordering among visits to group-practice physicians.


METHODS
Cross-sectional study using data from the 2005 and 2006 National Ambulatory Medical Care Surveys.


METHODS
Visits by adults to non-federally-funded, non-hospital-based group practices. Primary analyses focused on visits to physician owners; secondary analyses focused on visits to non-owners.


METHODS
Ordering of five laboratory tests: complete blood count (CBC), electrolytes, glycoslyated hemoglobin A1c (HbA1c), cholesterol, and prostate-specific antigen (PSA).


RESULTS
There were 19,163 visits to group-practice owners with 51.9% to a practice with an on-site laboratory. Visits to primary care physicians were more likely to be to a practice with an on-site laboratory when compared with visits to specialists (64.4% vs. 34.0%, p < 0.001). Among visits to specialist group owners, all five tests were ordered more often if there was an on-site laboratory, even after accounting for patient and practice characteristics: CBC: adjusted odds ratio[OR] = 8.01, 95% Confidence Interval [CI], 5.00-12.82, p < 0.001; electrolytes: aOR = 3.51, 95% CI, 1.93-6.40, p < 0.001; HbA1c: aOR = 4.91, 95% CI, 1.75-13.78, p = 0.003; cholesterol: aOR = 3.32, 95% CI, 1.85-5.93, p < 0.001; and PSA: aOR = 3.84, 95% CI, 1.93-7.65, p < 0.001. This association was not found among visits to primary care physician owners and all practice non-owners (both primary care and specialists). The estimated excess spending on these five tests by specialist owners with on-site laboratories was $75 million per 100 million visits.


CONCLUSIONS
In a nationally representative sample of visits to physician-owned group practices, specialist owners with on-site laboratories were more likely to order five common laboratory tests, potentially resulting in millions in excess healthcare spending.
Division of General Internal Medicine, Mount Sinai School of Medicine, New York, NY 10029, USA. taraf@alum.mit.edu
Tara F
TF
Bishop
Alex D
AD
Federman
Joseph S
JS
Ross
D003430:Cross-Sectional Studies; D003955:Diagnostic Tests, Routine / Q000191:economics* / Q000941:ethics; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009819:Office Visits / Q000191:economics; D018584:Physician Self-Referral / Q000941:ethics; D010818:Practice Patterns, Physicians' / Q000191:economics* / Q000941:ethics; D012052:Reimbursement, Incentive / Q000191:economics* / Q000941:ethics / Q000639:trends