Maggie Guo

Mean Abnormal Result Rate: Proof of Concept of a New Metric for Benchmarking Selectivity in Laboratory Test Ordering.

OBJECTIVES There is a need to develop and validate new metrics to access the appropriateness of laboratory test requests. METHODS The mean abnormal result rate (MARR) is a proposed measure of ordering selectivity, the premise being that higher mean abnormal rates represent more selective test ordering. As a validation of this metric, we compared the abnormal rate of lab tests with the number of tests ordered on the same requisition. We hypothesized that requisitions with larger numbers of requested tests represent less selective test ordering and therefore would have a lower overall abnormal rate. RESULTS We examined 3,864,083 tests ordered on 451,895 requisitions and found that the MARR decreased from about 25% if one test was ordered to about 7% if nine or more tests were ordered, consistent with less selectivity when more tests were ordered. We then examined the MARR for community-based testing for 1,340 family physicians and found both a wide variation in MARR as well as an inverse relationship between the total tests ordered per year per physician and the physician-specific MARR. CONCLUSIONS The proposed metric represents a new utilization metric for benchmarking relative selectivity of test orders among physicians.

Yearly Clinical Laboratory Test Expenditures for Different Medical Specialties in a Major Canadian City.

OBJECTIVES Very little is known about the relative contributions of physician specialty groups and individual physicians to overall clinical laboratory expenditures. The objectives of this study were to determine the costs of clinical laboratory test expenditures attributable to 30 medical specialties and the associated per capita physician expenditures for an entire major Canadian city. Only chemistry, hematology, and microbiology tests were included in this study. METHODS Retrospective cohort study involving all physicians in Calgary, Canada, and surrounding areas (n = 3,499) and secondary data on laboratory test orders. RESULTS Data were obtained on approximately 20 million test requests. The mean clinical laboratory test expenditure, in Canadian dollars, per physician was

A population study of fasting time and serum prostate-specific antigen (PSA) level.

27,945 for all physicians combined. Total expenditures by primary care physicians (family physicians and general practitioners) accounted for 58% of total expenditures. CONCLUSIONS There was wide variation in clinical laboratory test expenditures among specialties and on a per capita basis within medical specialties.

The incidence of acute myeloid leukemia in Calgary, Alberta, Canada: a retrospective cohort study

Prostate cancer is one of the most common cancers in men. Traditional screening and diagnostic methods include digital rectal examinations (DREs), biopsies and serum prostate-specific antigen (PSA) tests, with the latter being the more popular. PSA is a biomarker for prostate cancer; however, it is highly sensitive to external factors as well as other prostate diseases. As such, the reliability of of the serum PSA level as a sole screening and diagnostic tool for prostate cancer is controversial. Recently, it has been shown that fasting extremes can affect concentrations of serum chemistry analytes, thus raising the question of whether or not fasting has an effect on the highly sensitive PSA biomarker. Patients testing for serum PSA levels are often concomitantly submitting to other tests that require fasting, subjecting certain patients to a fasting PSA level while others not. The objective of this study was to investigate whether this discrepancy in fasting state translates into an effect on serum PSA levels. Serum PSA levels and fasting time records for 157 276 men who underwent testing at Calgary Laboratory Services (CLS; Calgary, Alberta, Canada) between 01 January 2010 and 31 March 2013 were accessed. Linear regression models of mean PSA levels and fasting times revealed a statistically important relationship at certain fasting times. Applying a dynamic mathematical model to explore the clinical effect of fasting suggests minimal impact on serum PSA result interpretation. Thus, patients can be tested for serum PSA levels regardless of their fasting state.

Use of geospatial mapping to determine suitable locations for patient service centers for phlebotomy services.

BackgroundThe incidence rate of acute myeloid leukemia (AML) was determined in the Calgary Metropolitan Area, a major Canadian city.MethodsData from all patients diagnosed with AML between January 1, 2011 and December 31, 2015 were retrieved from a single, centralized cancer cytogenetics laboratory for bone marrow samples, the sole diagnostic facility of its kind in Southern Alberta.ResultsThe calculated incidence rate was 2.79 cases per 100,000 person-years with a median age of 60, slightly lower than previously published data. The age-standardized incidence rate for Canada was 3.46 cases per 100,000 person-years. The higher value is reflective of Calgary’s younger population compared to the rest of Canada. Higher male incidence and greatest incidence occurring at approximately the age of 85 is similar to data from other developed countries. The lower incidence rates and median age of diagnosis, in comparison with that of other high-income nations, may be due to differences in the proportion of aging citizens in the population.ConclusionThis is the first published incidence rate of acute myeloid leukemia (AML) in Canada across all age groups.

Use of the Mean Abnormal Result Rate (MARR) to Gauge Changes in Family Physicians’ Selectivity of Laboratory Test Ordering, 2010-2015

OBJECTIVES Approaches to determining optimal locations for patient service centers (phlebotomy clinics) have not been addressed in the published literature. Using the city of Calgary, Alberta, Canada, as a test case, our objective is to present a novel method for determining underserviced geographic areas within a city to guide the choice of potential new patient service center locations. METHODS Data on travel distances for 198,883 phlebotomy visits as well as population data from the 2011 Canada Census were used for this study. Using geospatial mapping techniques, we produced maps of the city showing actual relative travel distances for patients as well as the geographic distribution of population density of patients undergoing phlebotomies. RESULTS There was a striking pattern of increased travel distances in certain parts of the city. These also corresponded to geographic areas with greater density of patients seeking phlebotomies. CONCLUSIONS This analysis provided clear, objective evidence of communities that are currently relatively underserved by patient service centers. This approach could be used by other laboratories to plan the location of new patient service centers.

Re: fasting times in serum PSA assay

Objectives The mean abnormal result rate (MARR) has recently been advanced as a metric of laboratory test appropriateness. We used the MARR metric to examine patterns of change in family physician test requisitions over time. Methods We accessed the Laboratory Information System of Calgary Laboratory Services for family physician-ordered testing on outpatients to gather aggregate test and abnormal result counts from 2010 to 2015. Results Over the 6 years, there was an annual average of 3,401,553 tests for 411,295 distinct patients on their first test requisition for the year. The MARR increased from 8.1% to 9.0% through this period. Conclusions The MARR for Calgary and surrounding area gives tentative evidence of a gradual increase in physician test selectivity in recent years. Further data from other catchment areas are needed before making assertions about broader trends in physician awareness of laboratory resource use.

Incidence of acute lymphocytic leukemia in Calgary, Alberta, Canada: a retrospective cohort study

clinical effect. The authors recommend that the optimal time to obtain an accurate PSA level is fasting for 7–9 h, which avoids the increased PSA levels observed with fasting extremes as well as possible diurnal rhythm variations that may exist in shorter fasting times. This is an interesting study with meaningful results. The authors have addressed obvious limitations such as potential recall errors by the patients and the nonrandomness of the cohorts. Based on these findings, it seems that fasting time may not be a concern for prostate cancer screening as the small variations (∼1%) is unlikely to change the PSA value over or under the threshold for most patients. However, for patients monitored for disease recurrence such as those after surgery or radiation for high risk prostate cancer, or for patients with advanced prostate cancer treated with conventional hormonal therapy or the newer agents, testing PSA under similar fasting conditions (7–9 h) may be advisable for consistent testing, since the trend in serial PSA tests are critical for clinical decision-making.