About

Daniel K. Colby, M.D. is an Associate Professor in the Department of Emergency Medicine at UC Davis Health and serves as the Medical Director of the Department of Emergency Medicine. His specialties include Emergency Medicine, Toxicology, and Addiction Medicine. Dr. Colby is also the Addiction Medicine fellowship director and leads the Substance Use Intervention Team (SUIT). His academic interests encompass health equity, clinical operations, substance use disorders, critical care toxicology, health technology, and medical education. He completed his undergraduate degree in Neuroscience at UCLA, earned his M.D. from UC Irvine College of Medicine, and completed his residency in Emergency Medicine at UC Davis Medical Center, followed by a fellowship in Medical Toxicology at the same institution. Dr. Colby has received multiple honors, including Sacramento Magazine's Top Doctors Award for several years and awards from UC Davis Health. His research and clinical work focus on emergency medicine, toxicology, addiction, and substance use interventions.

Research topics

• Medicine
• Family medicine
• Internal medicine
• Toxicology
• Emergency medicine
• Pharmacology
• Surgery
• Physical therapy
• Intensive care medicine
• Medical emergency
• Demography

Selected publications

• Cost-Effective Drug Testing: Analytical Methodology, Best Practices, and Clinical Utility

  The Journal of Applied Laboratory Medicine · 2025-01-01 · 6 citations

  review

  BACKGROUND: Drug overdose-related deaths continue to increase globally. Testing demands have likewise increased, prompting healthcare facilities to adopt a range of methods, from simple point-of-care immunoassays to comprehensive chromatographic and mass spectrometry-based techniques. Each of these testing methods has trade-offs related to cost, performance, speed, and convenience, requiring healthcare facilities to carefully determine the best options to meet their clinical needs. Unfortunately, current testing practices may result in unnecessary costs and certain methods, such as immunoassays, have significant limitations that affect their clinical utility. As such, the goal of this review is to frame the current state of drug testing and related cost-effectiveness and patient centered approaches to address this evolving public health challenge. CONTENT: This review discusses the current state of substance use mortality/morbidity, the economic impact of substance use disorders, provides an overview of testing methods and their relative cost-benefit, solutions to improve test utilization and cost-effectiveness, and finally, future threats and new opportunities that can improve the clinical utility of these tests. SUMMARY: The cost-effectiveness of drugs of abuse testing revolves around proper test utilization, including understanding what test is being ordered, its limitations, understanding results, and ordering testing when it can provide actionable information. Fundamental principles of test utilization such as education, clinical informatics, and optimizing test panels remain essential. Future threats in this space include new compounds and regulatory changes. However, novel solutions such as new noninvasive sample types, automation, and artificial intelligence can play a significant role in improving overall test utilization practices.

  PublisherDOI

• 110: BUPRENORPHINE INITIATION IN PATIENTS WITH ACUTE BURNS AND OPIOID USE DISORDER

  Critical Care Medicine · 2025-01-01

  article
  PublisherDOI

• Alcohol Use Disorder

  Cambridge University Press eBooks · 2025-06-26

  book-chapter1st authorCorresponding
  PublisherDOI

• The Toxicology Investigators Consortium 2022 Annual Report

  Journal of Medical Toxicology · 2023 · 16 citations

  • Medicine
  • Emergency medicine
  • Family medicine
  PublisherOA PDFDOI

• Buprenorphine Inductions via Transdermal Patches for Opioid Use Disorder in the Inpatient Setting

  Journal of Pain & Palliative Care Pharmacotherapy · 2023-06-16 · 3 citations

  articleSenior author

  Buprenorphine inductions traditionally require an opioid-free period due to the risk of precipitated opioid withdrawal. Hospitalized patients with opioid use disorder and concurrent acute pain may be eligible for buprenorphine therapy. However, effective buprenorphine induction strategies in this patient population have not been well established. Investigators sought to review the completion of a low dose induction protocol that does not require an opioid-free period prior to buprenorphine initiation. Hospitalized patients who completed a 7-day low dose induction protocol via buprenorphine transdermal patches October 2021 - March 2022 were examined via retrospective chart review (N = 7). All seven patients completed the induction and were discharged on sublingual buprenorphine. Low dose transdermal buprenorphine provides a reasonable strategy for hospitalized patients on full agonist opioid therapy or those who have failed conventional buprenorphine induction strategies. Reducing barriers such as opioid abstinence is key to combating opioid use disorder.

  PublisherDOI

• Urine Drug Testing in Patients Prescribed Long-Term Opioid Therapy: Associations with Patient and Prescriber Factors

  Pain Management · 2023-01-01

  articleOpen access

  <h3>Context:</h3> National guidelines recommend that patients with chronic non-cancer pain prescribed long-term opioid therapy (LTOT) undergo periodic urine drug testing (UDT), yet little evidence supports the utility of this approach. Given the wide variation in test utilization and interpretation, it is important to understand factors associated with UDT. <h3>Objective:</h3> To identify patient and prescriber factors associated with UDT in primary care patients prescribed LTOT. <h3>Study Design and Analysis:</h3> One-year retrospective cohort study of primary care patients prescribed LTOT by clinicians. Data extracted from the health system electronic medical record. Negative binomial regression examined patient and prescriber factors associated with the number of tests received, and logistic regression estimated prescriber propensity to order testing. Analyses were adjusted for patient and provider characteristics and accounted for patient clustering within prescribers. <h3>Setting:</h3> Primary care network in Northern California. <h3>Population:</h3> Adult primary care patients (N=5,690) prescribed LTOT (&gt;3 opioid prescriptions) and their providers. <h3>Outcome Measures:</h3> Any UDT and total number of UDT during the study year. <h3>Results:</h3> A total of 2,256 patients (39.6%) had UDT completed at least once. More UDT was associated with patients identifying as Black (vs white) race [adjusted incidence rate ratio (aIRR) = 1.2, 95% CI 1.0-1.4] and receipt of more opioid prescriptions [aIRR = 1.1, 95% CI 1.1-1.1]. Asian (vs white) patients were tested less [aIRR = 0.7, 95% CI 0.5-1.0]. Prescriber factors significantly associated with more testing included female (vs male) sex [aIRR = 1.3, 95% CI 1.0-1.5] and Internal Medicine (vs Family Medicine) specialty, [aIRR = 1.6, 95% CI 1.3-1.9]. Provider propensity for testing was also significant [rho=0.21, 95% CI 0.16-0.26]. <h3>Conclusions:</h3> UDT was relatively infrequent in patients prescribed LTOT and associated with patient race, which is not an opioid-related risk factor. Additionally, there was significant provider-driven variation in UDT. The findings are concerning, given the uncertain clinical utility of such testing and potentially high consequences for clinical decision-making, and signal the need for strategies to address potential biases in the use of UDT.

  PublisherOA PDFDOI

• Urine Drug Testing Among Patients Prescribed Long-Term Opioid Therapy: Patient and Clinician Factors

  The Journal of the American Board of Family Medicine · 2023-07-19 · 4 citations

  articleOpen access

  INTRODUCTION: National guidelines recommend that patients with chronic noncancer pain prescribed long-term opioid therapy (LTOT) undergo periodic urine drug testing (UDT), yet UDT is performed inconsistently, and little evidence supports the utility of this approach. We examined patient and prescriber factors associated with UDT. METHODS: A 1-year retrospective cohort study of 5690 patients prescribed LTOT by 689 clinicians in a network of 13 primary care and specialty clinics. Negative binomial regression examined patient and prescriber factors associated with the number of tests completed, and logistic regression examined prescriber and practice level testing likelihood. Analyses were adjusted for patient and clinician characteristics and accounted for patient clustering within prescribers. RESULTS: A total of 2256 patients (39.6%) had UDT completed at least once. More UDT completion was associated with Black patient race and receipt of more opioid prescriptions, as well as with clinician testing compliance. CONCLUSIONS: UDT was relatively infrequent in patients prescribed LTOT and associated with patient factors not known to confer greater opioid-related risk, such as race. In addition, there was significant clinician-driven variation in UDT. Given the uncertain clinical utility of such testing, these findings signal the need for strategies to address potential biases in the use of UDT.

  PublisherOA PDFDOI

• The Toxicology Investigators Consortium Case Registry—the 2021 Annual Report

  Journal of Medical Toxicology · 2022 · 19 citations

  • Medicine
  • Toxicology
  • Pharmacology
  PublisherOA PDFDOI

• EDE

  2022-10-27

  report
  PublisherDOI

• Bodybuilding supplements leading to copper toxicity, encephalopathy, fulminant hepatic failure and rhabdomyolysis

  The American Journal of Emergency Medicine · 2020 · 15 citations

  Senior authorCorresponding
  • Medicine
  • Intensive care medicine
  • Physical therapy
  PublisherDOI

Frequent coauthors

• Marc Eckstein

  42 shared

• Chelsea S. Kidwell

  42 shared

• Rainy Huang

  University of California, Los Angeles

  36 shared

• Jill Haines

  University of Alberta

  36 shared

• Sidney Starkman

  University of California, Los Angeles

  36 shared

• Brian Buck

  University of Alberta

  36 shared

• Jeffrey L. Saver

  University of California, Los Angeles

  36 shared

• James Chenoweth

  University of California, Davis

  19 shared

Labs

• Emergency MedicinePI

Awards & honors

• Sacramento Magazine's Top Doctors Award, 2021, 2022, 2023, 2…
• UC Davis Health Chief of Staff Award, 2025
• UC Davis Health Diamond Doc Award, 2023