Patterns of Laboratory Testing Utilization Among Uveitis Specialists




Purpose


To examine the range of practice in laboratory testing utilization among a subset of uveitis specialists using a scenario-based survey.


Design


Cross-sectional survey.


Methods


A web-based survey consisting of 13 patient scenarios was presented to the Executive Committee and Trustees of the American Uveitis Society. The participants were allowed to choose preferred testing in a free-form manner. The patterns of test utilization were studied and the cost of the testing was calculated based on Noridian Medicare reimbursal rates for Seattle, Washington.


Results


Nearly all providers recommended some testing for all scenarios. Forty-five different tests, including laboratory investigations and imaging and diagnostic procedures, were ordered. The mean number of tests ordered per scenario per provider was 5.47 ± 2.71. There was limited consensus among providers in test selection, with most tests in each scenario ordered by fewer than half of the providers. Average cost of testing per scenario per provider was $282.80, with 4 imaging tests (fluorescein angiography, magnetic resonance imaging, chest radiograph, and chest computed tomography) together contributing 59.9% of the total testing costs.


Conclusions


Uveitis specialists have a high rate of laboratory testing utilization in their evaluation of new patients. There is substantial variability in the evaluations obtained between providers. Imaging tests account for the majority of evaluation cost. The low agreement on specific testing plans suggests need for evidence-based practice guidelines for the evaluation of uveitis patients.


Uveitic conditions are commonly encountered in ophthalmology practice, with estimated incidence in large epidemiologic studies in the United States of approximately 50 per 100 000 person-years. This suggests approximately 150 000 incident cases in the United States each year. Determination of the etiology of uveitic disease typically entails laboratory testing. This testing is essential to ensure that treatable infectious diseases are identified and appropriately treated; to identify possible comorbid systemic disease associations that should be evaluated and potentially treated; and to provide prognostic information for the patient and physician. Retrospective studies have suggested that a definitive etiology (either infectious or associated with a systemic condition) is found overall in 26%–40% of patients in a tertiary referral setting.


A detailed history, review of systems, and accurate physical examination are essential in guiding the appropriate diagnostic tests in the evaluation of uveitis. There is no “standard laboratory workup” for uveitis, and unfocused ordering of diagnostic tests can be difficult to interpret and costly. Over-testing may lead to improper treatment as well, owing to false-positive results. Clinicians ordering laboratory testing are primarily interested in the positive predictive value (the probability that the patient has a given condition, given a positive test) and the negative predictive value (the probability that the patient does not have disease, given a negative test). These values can be calculated using Bayesian statistics for a given test if the sensitivity and specificity of the test are known, as well as the prevalence of the condition in the tested population. However, the result of a particular test must be interpreted with caution, given that the predictive parameters of each test can vary in different settings.


As cost containment becomes more prevalent in medical practice, scrutiny of laboratory testing practices is increasing. At present, there are no global practice guidelines for laboratory testing in uveitis. The purpose of the present study was to examine the range of practice in laboratory testing utilization among a subset of uveitis specialists and determine its cost implications.


Methods


A web-based survey was presented to the Executive Committee and Trustees of the American Uveitis Society. The University of Washington Institutional Review Board approval was waived for this research, and the study was in adherence to the Declaration of Helsinki. The survey included 13 hypothetical clinical case-based scenarios ( Supplementary Table ; Supplemental Material available at AJO.com ). The scenarios were designed to be representative of real-life diagnostic challenges. For none of the cases was an exclusive diagnosis strongly suggested by the history and findings. For each scenario, participants were asked to list the investigations that they would order. A comprehensive list of laboratory investigations, imaging modalities, and diagnostic procedures were included as a guide, but the participants were allowed to specify any testing they desired. The survey also included 5 additional questions regarding the practice pattern of the responding physicians.


The descriptive statistics and all analyses were performed with R ( www.r-project.org ). The cost of the testing was calculated based on 2013 Noridian Medicare reimbursement rates for Seattle, Washington.




Results


Twelve of 14 members of American Uveitis Society executive committee and trustees responded to the survey. One physician reported not having a majority uveitis practice (seeing fewer than 50 new uveitis patients a year) and was excluded from the analysis. The mean number of years since completion of fellowship was 17.16 (range 8–32). Fifty-percent were hospital based and 50% outpatient office based. Of the respondents, 45.45% saw approximately 101–250 new uveitis patients annually, while 27.27% each saw either between 51 and 100 or greater than 250. Demographics of respondents are shown in Table 1 .



Table 1

Practice Patterns of Survey Participants
























































































Provider ID # of New Uveitis Patients Annually Primary Practice Site a Consideration of the Patient’s Insurance Status Years in Practice Majority Uveitis Practice
1 101–250 Outpatient Weakly 24 True
2 51–100 Hospital Weakly 8 True
3 101–250 Hospital Moderately strongly 11 True
4 101–250 Outpatient Not at all 8.75 True
5 >250 Outpatient Moderately strongly 32 True
6 101–250 Hospital Moderately strongly 8 True
7 >250 Hospital Moderately strongly 20 True
8 51–100 Outpatient Not at all 25 True
9 51–100 Hospital Moderately strongly 8 True
10 101–250 Outpatient Moderately weakly 29 True
11 >250 Hospital Moderately weakly 15 True

a Outpatient: outpatient, office-based; hospital: hospital-based.



The details of the specific tests ordered by each physician are summarized in Table 2 . A total of 782 investigations were ordered by the 11 providers for the 13 scenarios. Forty-five different tests, including laboratory tests and imaging and diagnostic procedures, were ordered. The mean number of tests ordered per case scenario per provider was 5.47 ± 2.71; the median was 5.0 ( Figure 1 ). In aggregate, the highest number of tests was ordered for Scenario 5 (46-year-old man with prior Bacillus Calmette-Guérin [BCG] vaccine presenting with positive purified protein derivative [PPD] test presenting with bilateral perivenous sheathing, unilateral neovascularization and vitreous hemorrhage, 83 tests, 7.54 tests per provider) and the lowest for Scenario 12 (27-year-old woman with unilateral acute anterior uveitis in the setting of known ulcerative colitis, 31 tests, 2.82 tests per provider). The highest test utilizer ordered 105 tests (average of 8.18 tests/scenario), while the lowest ordered 54 tests (average 4.15/scenario). In only 3 instances (2.1% of opportunities) did any provider decline to order laboratory testing (Scenarios 12 and 13).



Table 2

Specific Tests Ordered per Scenario by All Responders (N = 11)




























































Scenario Tests Ordered Average Number of Tests
1 ACE (3), CBC (1), CT chest (1), CXR (8), HLA-B27 (11), Lyme (2), Lysozyme (1), OCT (1), PPD (2), RPR (5), Syphilis ab (10) 4.09
2 A1C (1), ACE (4), ANA (1), B2 microglobulin (4), Bartonella (1), CBC (8), CMP (5), CXR (10), Creatinine (4), ESR (4), FA (4), Fundus photo (1), HIV (1), Lyme (2), Lysozyme (1), MRI brain (1), OCT (3), PPD (2), QuantiFERON (1), RF (1), RPR (5), Syphilis ab (10), UA (6) 7.27
3 ACE (5), ANA (2), CBC (6), CMP (5), CT chest (3), CXR (9), ESR (2), FA (7), ICG (1), Lyme (2), Lysozyme (2), MRI brain (1), OCT (6), PPD (4), QuantiFERON (1), RF (1), RPR (4), Skin biopsy (1), Syphilis ab (11), UA (1), Viral PCR (1) 6.82
4 ACE (5), CBC (2), CMP (2), CT chest (2), CXR (9), ESR (1), FA (5), Fundus photo (1), HLA-A29 (1), HTLV (1), Lyme (4), Lysozyme (1), MRI brain (5), OCT (8), PPD (3), RPR (4), Syphilis ab (11) 5.91
5 ACE (4), ANA (2), ANCA (1), Bartonella (2), CBC (4), CMP (3), CRP (2), CT chest (4), CXR (8), ESR (3), FA (9), Fundus photo (1), HIV (1), HLA-B51 (1), HTLV (1), Lupus ab (1), Lyme (3), Lysozyme (2), OCT (1), PPD (1), QuantiFERON (8), RF (2), RPR (4), Syphilis ab (10), Toxoplasmosis ab (1), West Nile (1), anti-CCP (1), anti-RNP (1), anti-SS (1) 7.55
6 ACE (1), ANA (10), CBC (5), CMP (2), CXR (4), ESR (1), HLA-B27 (2), Lyme (2), Lysozyme (1), OCT (5), PPD (1), RF (2), RPR (1), Syphilis ab (3) 3.64
7 Bartonella (3), CBC (6), CMP (2), CXR (4), Creatinine (1), Fundus photo (2), HIV (1), ICG (1), Liver panel (1), Lyme (1), PPD (4), QuantiFERON (1), RPR (1), Syphilis ab (8), Toxocara ab (1), Toxoplasmosis ab (10) 4.27
8 ACE (2), ANA (1), ANCA (1), CBC (5), CMP (4), CXR (6), ESR (1), FA (2), Fundus photo (2), HIV (3), HLA-B27 (1), HLA-B51 (1), Lyme (2), MRI brain (1), PPD (3), RPR (6), Syphilis ab (10), Toxoplasmosis ab (4), UA (2), Viral PCR (8) 5.91
9 ANA (6), ANCA (11), CBC (6), CMP (4), CRP (4), CXR (6), Creatinine (2), ESR (7), Lyme (2), PPD (2), RF (7), RPR (1), Syphilis ab (8), UA (5), anti-CCP (5) 6.91
10 ACE (3), CBC (7), CMP (4), CT chest (2), CXR (9), ESR (1), FA (5), Fundus photo (1), HTLV (1), Lyme (4), Lysozyme (1), MRI brain (4), OCT (3), PPD (4), RPR (4), Syphilis ab (10), UA (1), Viral PCR (1) 5.91
11 ACE (4), CBC (5), CMP (4), CT chest (2), CXR (6), Creatinine (2), ERG (2), FA (7), Fundus photo (2), GVF (1), HLA-A29 (9), HVF (2), Hepatitis panel (1), ICG (3), Liver panel (1), Lyme (2), Lysozyme (1), OCT (6), RPR (5), Syphilis ab (9), UA (1) 6.82
12 ACE (1), CBC (2), CMP (1), CXR (5), ESR (2), HLA-B27 (8), Lyme (1), PPD (1), RPR (4), Syphilis ab (6) 2.82
13 ACE (2), CXR (7), HLA-B27 (10), Lyme (2), Lysozyme (1), PPD (1), RPR (4), Syphilis ab (8) 3.18

A1C = Hemoglobin A1C; ACE = angiotensin-converting enzyme; ANA = antinuclear ab; ANCA = antineutrophil cytoplasmic ab; anti-CCP = anti–cyclic citrullinated peptide ab; anti-RNP = anti-ribonucleoprotein ab; anti-SS = anti–Sjogren syndrome ab; CBC = complete blood count; CT = computed tomography; CXR = chest radiograph; ESR = erythrocyte sedimentation rate; FA = fluorescein angiography; HTLV = human T-cell lymphotropic virus; ICG = indocyanine green angiography; Lupus ab = lupus anticoagulant; MRI = magnetic resonance imaging; OCT = optical coherence tomography; PCR = polymerase chain reaction; PPD = purified protein derivative test; RF = rheumatoid factor; RPR = test including rapid plasma reagin and venereal disease research laboratory test; Syphilis ab = test including fluorescent treponemal antibody (ab), microhemagglutination assay, and treponema pallidum particle agglutination; Toxocara ab = toxocara IgM or IgG; Toxoplasmosis ab = toxomplasmosis IgM or IgG; UA = urinalysis with microbiology.



Figure 1


Distribution of the total number of ordered tests per scenario by each provider.


The total number of times any test could be ordered was 143 (13 scenarios multiplied by 11 respondents). The frequency of each specific test being ordered in this study, the cost per test, and the total cost of the ordered tests are presented in Table 3 . The most commonly ordered tests were treponemal antibody tests (ie, fluorescent treponemal antibody – absorption test, treponema pallidum particle agglutination, or microhemagglutination assay [114 of 143 possible orders, 79.72%]), followed by chest radiography (91, 63.63%), complete blood count (57, 39.86%), non–treponemal tests (ie, rapid plasma reagin or venereal disease research laboratory test; 48, 33.57%), purified protein derivative/QuantiFERON (39, 27.27%), fluorescein angiogram (39, 27.27%), and angiotensin-converting enzyme (34, 23.78%). Remarkably, there was almost no consensus on evaluation between providers ( Figure 2 ). Only for 1 test (antineutrophil cytoplasmic antibody) for 1 scenario (Scenario 9, unilateral scleritis) was there universal agreement. Most laboratory tests were ordered by less than half of the participants ( Figure 2 ).



Table 3

Details of the Frequency of the Ordered Tests and the Associated Costs of All 13 Clinical Scenarios from 11 Uveitis Providers































































































































































































































































Diagnostic Test Number of Orders Cost per Order ($) Total Cost ($)
Tests With No Diagnostic Value
CBC 57 8.9 507.3
CMP 36 14.5 522
Creatinine 9 7 63
Hgb A1C 1 13.3 13.3
Liver panel 2 11.2 22.4
Hepatitis panel 1 20.1 20.1
ESR 22 3.7 81.4
CRP 6 7.1 42.6
Ocular Tests
Fundus photo 10 69.2 692
FA 39 199.2 7768.8
ICG 5 199.2 996
OCT 33 56.5 1864.5
HVF 2 75.1 150.2
GVF 1 50.5 50.5
ERG 2 121.9 243.8
Viral PCR 10 196 1960
Non–Ocular Tests
ACE 34 20.1 683.4
Lysozyme 11 25.8 283.8
ANA 22 16.6 365.2
ANCA 13 17.8 231.4
RF 13 7.8 101.4
anti-CCP 6 17.8 106.8
anti-RNP 1 24.7 24.7
anti-SS 1 49.3 49.3
HLA-B27 32 37.7 1206.4
HLA-A29 10 33.1 331
HLA-B51 2 81.9 163.8
Syphilis ab 114 18.2 2074.8
RPR 48 6.1 292.8
HIV 6 33.1 198.6
HTLV 3 11.5 34.5
Bartonella 6 48.2 289.2
Lupus ab 1 11.7 11.7
Lyme ab 29 23.4 678.6
Toxocara ab 1 17.9 17.9
Toxoplasmosis ab 15 19.8 297
West Nile 1 58.9 58.9
PPD 28 6 168
QuantiFERON 11 103 1133
UA with micro 16 4.4 70.4
Urine B2 4 20 80
Skin biopsy 1 0 0
MRI brain 12 539.7 6476.4
CT chest 14 307 4298
Chest XR 91 62.8 5714.8
Total 782 2677.7 40 439.7
Per provider 3676.34
Per scenario per provider 282.80

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Jan 5, 2017 | Posted by in OPHTHALMOLOGY | Comments Off on Patterns of Laboratory Testing Utilization Among Uveitis Specialists
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