Physicians and Physician Assistants Practice in Substantially Similar Fields Under Iowa’s Medical-Expert Qualification Statute

1. Introduction

In Joshua Davenport v. Nathanael K. Fuller, the Iowa Supreme Court clarified when a physician may provide the expert support required for a medical-malpractice action against a physician assistant. The court held that physicians licensed under Iowa Code chapter 148 and physician assistants licensed under chapter 148C practice in “substantially similar fields” for purposes of Iowa Code section 147.139(1) and (2).

The decision extends the categorical approach adopted earlier in Jones v. Lindell. Under that approach, a healthcare provider’s statutory “field” corresponds to the provider’s professional license—not the provider’s particular specialty, workplace, or patient population. Consequently, the difference between a surgeon working in an emergency department and a physician assistant providing outpatient primary care did not determine their field-level compatibility.

The opinion establishes an important qualification: substantial similarity between professional fields does not make expert eligibility fully reciprocal. Section 147.139(4) independently requires an expert testifying against a licensed-physician defendant to be a licensed physician.

2. Background and Procedural History

Joshua Davenport consulted his primary care provider, physician assistant Nathanael Fuller, twice in March 2023 because of abdominal pain and difficulty urinating. Fuller initially diagnosed urinary retention associated with a probable enlarged prostate and prescribed medication. At the second visit, Fuller advised Davenport that he could double the dosage; the following day, Fuller referred him for a urology consultation.

Davenport’s condition worsened, and he subsequently sought emergency treatment. He had acute diverticulitis rather than the condition Fuller had diagnosed. Davenport suffered a perforated bowel, feculent peritonitis, and septic shock, requiring several weeks of hospitalization.

Davenport sued Fuller for negligence, alleging an inadequate examination and a treatment course that allowed the undiagnosed diverticulitis to progress. He claimed serious physical injuries and lost work.

To satisfy Iowa’s certificate-of-merit requirement, Davenport timely served an affidavit signed by Dr. Cass Franklin, an Iowa-licensed physician board-certified in surgery. Franklin described experience involving surgery, trauma, urgent care, and emergency medicine. Davenport also designated Franklin as his sole trial expert.

After the deadline for designating additional experts expired, Fuller sought dismissal. He argued that a surgeon lacked the qualifications required to address the standard of care applicable to a physician assistant practicing family medicine. The district court agreed, emphasizing the differences between Franklin’s surgical practice and Fuller’s primary care practice.

The Iowa Supreme Court reversed. Justice Oxley authored the opinion, joined by all participating justices. Chief Justice Christensen did not participate.

3. Summary of the Opinion

The court resolved both a procedural objection and the substantive qualification question:

1. Davenport preserved the statutory issue. His district court arguments sufficiently challenged Fuller’s specialty-based interpretation of “field.” The more developed textual arguments on appeal supported the same preserved claim.
2. “Field” is defined categorically by licensure. Particular practice areas within a license do not establish different fields under section 147.139(1) and (2).
3. Physicians and physician assistants occupy different, but substantially similar, fields. Their licenses are not identical, but their statutory definitions, authorized medical services, regulatory relationships, and educational structures establish substantial similarity.
4. Franklin satisfied the disputed qualification requirements. The parties also did not dispute that he had practiced under his physician’s license during the relevant five-year period.
5. Dismissal was improper. Davenport had timely supplied a certificate of merit signed by a qualified expert.

The decision did not determine whether Fuller breached the applicable standard of care, whether any breach caused Davenport’s injuries, or what damages Davenport could recover. Those questions remained for further proceedings.

4. The Statutory Framework

A. The 2017 Change in Expert Qualifications

Before 2017, section 147.139 focused on whether an expert’s qualifications related directly to the medical problems and treatment involved in the particular lawsuit. That language invited a case-specific comparison of the expert’s experience with the alleged malpractice.

The 2017 legislation replaced that approach with more categorical requirements and also introduced the certificate-of-merit affidavit requirement. Under the provisions discussed in the opinion:

• Section 147.139(1): The expert must be licensed in the same or a substantially similar field as the defendant.
• Section 147.139(2): During the five years preceding the allegedly negligent act or omission, the expert must have actively practiced in the same or a substantially similar field.
• Section 147.139(3): If the defendant is board-certified in a specialty, the expert must hold certification in the same or a substantially similar specialty.
• Section 147.139(4): If the defendant is a physician or osteopathic physician licensed under chapter 148, the expert must be a licensed physician.

Section 147.140(1)(a) makes these qualifications applicable to experts signing certificate-of-merit affidavits. The statutory requirements therefore operate at an early stage of litigation, not merely when a witness is offered at trial.

B. Distinguishing Fields from Specialties

The opinion preserves an essential distinction between professional licensure and specialty certification. A physician’s license identifies the relevant field; a certification in surgery, urology, or obstetrics and gynecology addresses a separate statutory inquiry.

The district court had effectively treated surgery and family medicine as different fields. Under the Supreme Court’s interpretation, that reasoning placed practice-area differences into the wrong statutory category. No separate matching-specialty question under subsection (3) controlled this appeal.

5. Precedents Cited and Their Influence

A. The Controlling Framework: Jones v. Lindell

Jones v. Lindell, 32 N.W.3d 445 (Iowa 2026), supplied the opinion’s central framework. There, a patient alleged negligence involving a hysterectomy and postoperative care. Her proposed expert was a board-certified urologist; the defendant physician was board-certified in obstetrics and gynecology.

The court held that both practitioners occupied the same “field” because both were licensed physicians practicing medicine. It nevertheless concluded that their specialties were not substantially similar, so the expert failed the separate certification requirement.

Jones v. Lindell defined substantially similar specialties as those sharing a high degree of likeness in their core characteristics, such that certification in one supplies the foundational knowledge and competence necessary to evaluate the other’s standard of care. It identified seven nonexclusive considerations:

1. Formal definitions;
2. Certifying board structures;
3. Required education and training;
4. Scope of practice;
5. Overlap in core and procedural competencies;
6. Professional association overlap; and
7. Hospital credentialing patterns.

The present opinion extends that framework to different licensed fields. The operative question becomes whether licensure in one field supplies the foundational knowledge and competence to evaluate the standard of care in the other. The factors are adaptable, not a mandatory checklist requiring identical evidence in every case.

The distinction between the cases matters. Jones v. Lindell involved the same field but insufficiently similar specialties. Davenport’s case involved different fields that were sufficiently similar. Thus, the earlier decision established the method without predetermining the outcome.

B. Preservation of the Statutory Issue

Lee v. State, 815 N.W.2d 731 (Iowa 2012)

This decision explains that preservation gives opposing counsel notice, an opportunity to respond, and a chance to pursue corrective measures or alternatives. Its treatment of a sovereign-immunity argument supported considering Davenport’s developed appellate argument because the essential statutory qualification dispute had already been presented below.

State v. Mann, 602 N.W.2d 785 (Iowa 1999)

The court cited this case through the quotation in Lee v. State. Its contribution was the practical explanation for preservation rules: fairness and an opportunity to address the disputed issue in the district court.

Bartlett Grain Co., LP v. Sheeder, 829 N.W.2d 18 (Iowa 2013)

This authority states that a party preserves an issue by alerting the court to its “essential claim.” Davenport satisfied that requirement by quoting the statute and arguing that Franklin and Fuller practiced in the same or substantially similar fields.

JBS Swift & Co. v. Ochoa, 888 N.W.2d 887 (Iowa 2016)

This case permits new legal authorities on appeal when they provide “additional ammunition” for a previously raised argument. Davenport’s more detailed textual analysis did not introduce a different claim; it strengthened his existing challenge to Fuller’s interpretation.

Christensen v. Iowa Dist. Ct., 21 N.W.3d 529 (Iowa 2025)

The court relied on this decision for the principle that statutory meaning is a judicial responsibility and courts need not adopt erroneous interpretations offered by the parties. This reinforced the court’s authority to interpret “field” correctly once the relevant issue was properly before it.

Ames 2304, LLC v. City of Ames, 924 N.W.2d 863 (Iowa 2019)

In that case, a dispute over whether remodeling increased the intensity of a nonconforming use preserved arguments about the statutory word “intensity.” The analogy supported review here: disputing expert eligibility under the statutory “field” requirement preserved the interpretation of that term.

C. Principles of Statutory Interpretation

Bribriesco-Ledger v. Klipsch, 957 N.W.2d 646 (Iowa 2021)

This decision supplies the presumption that words and phrases bear the same meaning throughout a statutory text. Because subsections (1), (2), and (3) all use “same” or “substantially similar,” the court applied a consistent understanding of substantial similarity to fields and specialties.

Wyciskalla v. Iowa Dist. Ct., 588 N.W.2d 403 (Iowa 1998)

This authority supports treating a statutory revision as a change in law when that intention is clear and unmistakable. It reinforced the conclusion that the 2017 amendments displaced the former treatment-specific qualification inquiry.

State v. Ahitow, 544 N.W.2d 270 (Iowa 1996)

The opinion cited this case through the quotation in Wyciskalla v. Iowa Dist. Ct.. Its role was to support giving substantive effect to legislative revisions rather than carrying the superseded statutory approach into the new text.

6. Analysis of the Court’s Legal Reasoning

A. Licensure Establishes the Proper Level of Comparison

The court reviewed the statutory questions for correction of errors at law. Its starting point was the legislature’s requirement that an expert be “licensed to practice” in the relevant field.

Because professional specialties do not each have separate licenses, defining “field” by a narrow practice area would detach the term from its statutory reference to licensure. The broader scheme confirms this interpretation: section 147.136A identifies healthcare providers by professional categories and their governing licensing provisions.

Franklin and Fuller did not hold the same license. Accordingly, the court could not treat their fields as identical. It instead examined whether the two licensing categories were substantially similar.

B. Shared Definitions and Medical Functions Supported Similarity

Iowa law defines both physicians and physician assistants through the practice of medicine. The court considered this overlap particularly significant because the statutory definition of medical practice expressly excludes several other healthcare professions.

The authorized services of physician assistants also substantially overlap with those of physicians. These include diagnosing and treating medical and surgical problems, prescribing medication, performing certain procedures, providing emergency services, and making referrals. Physician assistants may also direct other personnel involved in patient care.

The court acknowledged limits, including rules permitting physician assistants to assist physicians in surgery and obstetrical care rather than independently performing those services. Those distinctions did not defeat substantial similarity because the statute does not require identical authority.

C. Separate Regulatory Boards Were Not Dispositive

Physicians and physician assistants have separate licensing boards. In Jones v. Lindell, separate specialty-certification structures had supported a finding of dissimilarity. Here, however, the regulatory relationship included important connections.

The physician assistant board must consult the board of medicine before adopting licensure rules. Its membership must also include a physician licensed in medicine and surgery and a physician licensed in osteopathic medicine and surgery. These links distinguished the boards from the more independent certification structures considered in Jones v. Lindell.

The reasoning shows why the analysis is contextual: separate boards are relevant evidence, not an automatic bar to substantial similarity.

D. Education and Supervised Practice Reinforced the Connection

Both professions require approved education directed toward practicing medicine and examinations establishing professional qualification. Physician assistants must complete an accredited program and pass the national certifying examination.

The court also emphasized the two-year physician-supervision requirement before independent practice. The supervising relationship includes an understanding of the physician assistant’s scope of practice and areas of medicine performed. This structure supported the conclusion that the professions share a medical foundation, despite differences in training and authority.

E. The Particular Injury and Treatment Did Not Control Field Similarity

The decisive inquiry was not whether Franklin’s personal surgical experience closely matched Fuller’s outpatient work or Davenport’s particular presentation. Under the revised statute, the “actual problems or treatments at issue” do not determine whether licensed fields are substantially similar.

This limits the holding to the statutory comparison. It does not decide the underlying malpractice allegations or establish that every proposed medical opinion is admissible merely because its author satisfies the field requirement.

F. The Statute Expressly Addresses Asymmetry

Fuller argued against an interpretation that could permit physician assistants to testify against physicians. The court answered that subsection (4) already addresses that concern: experts against licensed-physician defendants must themselves be licensed physicians.

The provisions therefore work together. A physician can satisfy the field requirement in a case against a physician assistant, while a physician assistant cannot rely on field similarity alone to overcome the express restriction protecting physician defendants.

Finally, interpreting “substantially similar” to demand effectively identical professional categories would deprive that phrase of independent work. The court’s interpretation preserves the distinction between the “same” field and a different but sufficiently related field.

7. Potential Impact

A. Greater Predictability in Physician Assistant Malpractice Cases

The decision establishes that differences between a physician’s and a physician assistant’s particular practices do not defeat field-level eligibility under section 147.139(1) and (2). This reduces the risk of dismissal based on treating clinical subspecialization or workplace setting as a separate licensed field.

B. A Framework for Other Cross-Profession Disputes

Future courts can compare statutory definitions, scope of practice, regulatory structures, and education when evaluating other professional pairings. The inquiry concerns the licensing categories, not simply whether two practitioners sometimes perform overlapping tasks.

The opinion does not establish that all healthcare professions are substantially similar. Each proposed comparison requires its own analysis, and the court’s discussion of statutory exclusions from medical practice underscores the need for caution.

C. Continued Importance of Other Qualification Requirements

Field similarity does not replace active-practice requirements, applicable specialty-certification requirements, or the physician-only restriction. Litigants must assess each statutory condition separately.

The case also illustrates the practical stakes of selecting an expert early. A certificate-of-merit challenge can threaten the entire action, particularly after the deadline for designating additional experts has expired.

D. A Focused Preservation Lesson

Parties need not anticipate every appellate authority or articulate every textual argument in its final form below. They must, however, present the essential issue to the district court. The opinion permits refinement of a preserved argument; it does not authorize entirely new issues on appeal.

8. Complex Concepts Simplified

Prima facie medical-malpractice case

The initial showing needed to support a malpractice claim. Expert evidence is generally necessary to establish the professional standard of care and its breach.

Certificate of merit affidavit

An early sworn expert statement required by Iowa law in covered malpractice actions. Its signer must satisfy the statutory expert qualifications.

Categorical approach

A method that compares professional licensing or certification categories rather than deciding similarity from the particular injury or treatment in the lawsuit.

Field versus specialty

A field corresponds to a professional license, such as physician or physician assistant. A specialty is a separately certified area within a profession, such as surgery.

Substantially similar

Not identical, but sufficiently alike in core characteristics that the relevant license supplies foundational competence to evaluate the other field’s standard of care.

Error preservation

Presenting an issue sufficiently clearly in the trial court so that the court and opposing party have an opportunity to address it before appellate review.

Reversal and remand

The appellate court sets aside the challenged judgment and returns the case for further proceedings. Here, Davenport’s lawsuit continues; he has not yet won on negligence or damages.

The opinion also notes that Iowa’s 2026 legislation treats “physician assistant,” “physician associate,” and “P.A.” as synonymous. Its use of “physician assistant” follows the record and does not create a distinct legal category.

9. Conclusion

Joshua Davenport v. Nathanael K. Fuller establishes that physicians and physician assistants practice in substantially similar fields under Iowa’s medical-expert qualification statute. The comparison turns on professional licensure and the core characteristics of the licensed professions—not differences between surgery, emergency work, and outpatient primary care.

The decision allows Davenport’s claim to proceed while preserving the statute’s separate requirements for active practice, specialty certification, and experts against physician defendants. Its broader significance is a clearer, category-based framework for evaluating cross-profession medical experts without deciding the merits of the malpractice claim itself.