Potential savings of two practical interventions on vitamin D ordering practices at a large academic medical center

To the Editor,

Sustainable laboratory practices have become a topic of discussion in recent years focusing on strategies to lower environmental footprints, decrease costs, and improve patient safety [1], [2], [3], [4], [5]. Some methods that have been proposed include eliminating inappropriate testing, reducing blood collection tube sizes, switching to more eco-friendly reagents or quality control materials, and reducing use of single-use plastic consumables [1], [2], [3], [4], [5]. Serum 25-hydroxyvitamin D (25-OH vitamin D) is one test that has been a target for laboratory stewardship [2].

Vitamin D deficiency has been associated with musculoskeletal, cardiovascular, autoimmune, infectious, malignant, and metabolic disorders [6], 7]. However, a causal relationship between 25-OH vitamin D concentration and many disorders, as well as, the efficacy and safety of supplementation have yet to be established [2], 8], 9]. In addition, many laboratories utilize different testing modalities and thresholds for assessing vitamin D status through 25-OH vitamin D [2], 9]. Due to these limitations of 25-OH vitamin D testing, the 2024 Endocrine Society Clinical Practice Guideline for vitamin D recommends against routine 25-OH vitamin D testing for pregnant and non-pregnant adults >18 years [8]. Given these recent recommendations, our study aims to assess the frequency and costs of wasteful vitamin D testing in the adult primary care setting. In addition, we propose two practical solutions to reduce vitamin D testing waste including eliminating wasteful tests via a Clinical Decision Support (CDS) tool within the electronic medical record (EMR) and decreasing the blood collection tube size for appropriate 25-OH vitamin D testing across our institution.

The study qualified for exemption per §46.104(d)(4) by the International Review Board (IRB) (Protocol #241562). De-identified data on patient age, sex, and associated International Classification of Diseases, 10th Revision (ICD10) codes were collected for all 25-OH vitamin D tests resulted in our adult patient population (>18 years) across our institution from January 1, 2024 to December 31, 2024. ICD10 code Z00.00 (encounter for general adult medical examination without abnormal findings, age 15–124 years) was used to identify testing associated with adult annual primary care visits. Within the tests ordered during adult primary care visits, tests with 3+ ICD10 codes (i.e., complicated patient) or ICD10 codes associated with vitamin D, fatigue, or mood dysregulation were considered clinically appropriate (data not shown). Otherwise, all other tests were designated as “wasteful.”

Collection tube and non-recyclable packaging weights were measured for the currently utilized 5 mL collection tubes and smaller, alternative 3.5 mL collection tubes. Self pay costs for patients were gathered from our institutional website and cost to the laboratory was provided by an internal cost per test analysis. Estimates of the interventional effect on patient blood saved, non-recyclable waste eliminated, and financial costs avoided for patients and the clinical laboratory were calculated.

In 2024, 86,841 25-OH vitamin D tests resulted in the adult population (>18 years) across our institution. This included 82,350 (95 %) appropriate and 4,491 (5 %) wasteful tests. The majority (57 %) of wasteful tests were ordered in patients 18 to <50 years. Only 3 % of the wasteful tests were ordered in the 75+ years population (Table 1). In addition, 2,438 (2.8 %) 25-OH vitamin D tests were associated with the Z00.00 ICD10 code with no other associated codes.

One 25-OH vitamin D test cost a self-pay patient $89.76 and the laboratory $11.15 (excluding overhead costs). In addition, each 5 mL blood collection tube produced 8.041 g of plastic and Styrofoam (i.e., non-recyclable waste) as compared to the 3.5 mL blood collection tube which produced 6.841 g of non-recyclable waste.

By eliminating wasteful tests, 22,455 mL of patient blood, 36,112 g of non-recyclable waste, $403,112 for self-pay patients, and $50,075 for the clinical laboratory could be saved annually. Additionally, by changing from 5 to 3.5 mL blood collection tubes for appropriate 25-OH vitamin D testing, 123,525 mL of patient blood and 98,820 g of non-recyclable waste could also be saved annually. Together, this represents a total savings of 145,980 mL of patient blood, 134,932 g of non-recyclable waste, $403,112 of self-pay costs, and $50,075 of laboratory costs (Table 2).

Our study highlights the potential savings of two practical interventions to decrease our laboratory environmental impact, patient risk of iatrogenic anemia, patient healthcare spending, and laboratory financial costs of inappropriate 25-OH vitamin D testing. Previous efforts implementing a CDS tool within the EMR have shown to be effective in decreasing the number of 25-OH vitamin D test orders [10]. For implementation to be successful, educating patient providers about the change in guidelines and getting buy-in from both institutional leadership and patient providers would be important. Collaborating with providers within the clinical space could help champion the effort [3].

There are many recommendations for revising clinical laboratory practices to become more sustainable including reducing unnecessary testing, toxic chemicals, energy use, and single-use consumables [1], 3]. Given all the suggestions, our proposed changes represent a small step towards improving the environmental footprint of the clinical laboratory. In theory, a similar methodology to reduce wasteful testing and switch to smaller blood collection tubes could be used for other laboratory testing within an institution in accordance with the appropriate society guidelines.

Our proposed changes may also reduce unreimbursed patient medical expenses in the United States. We found that 2.8 % of the 25-OH vitamin D testing were solely associated with the Z00.00 ICD10 code. A rise in insurance claim denials associated with the use of the Z00.00 code has been previously noted [11] and also seen internally (data not shown). This suggests that 25-OH vitamin D tests without appropriate ICD10 codes may increase the chance of insurance claim denials and additional patient out-of-pocket healthcare costs.

Our study has certain limitations. Vitamin D ordering practices at our institution may not be generalizable across all hospitals in the United States. In addition, moving to the smaller 3.5 mL collection tubes might provide inadequate blood volume if there are multiple lab orders on the collection tube. Only using self-pay costs might not be representative of what a patient would pay if covered by a third-party insurer. However, it does provide a surrogate in contextualizing costs. Finally, adding a CDS tool within the EMR could result in alert fatigue for providers ordering the test and must be done carefully with appropriate clinician buy in.

Overall, our proposed changes promote high-value care with the potential for substantial impact on the environment, patient safety as well as patient and institutional spending.