UNITED STATES COURT OF APPEALS

FOR THE TENTH CIRCUIT

_________________________________

C.D.I., 

 Plaintiff - Appellant,

v.

COMMISSIONER, SSA, 

 Defendant - Appellee.

No. 23-1139

(D.C. No. 1:22-CV-00629-NYW)

(D. Colo.)

_________________________________

ORDER AND JUDGMENT*

_________________________________

Before MATHESON, EID, and CARSON, Circuit Judges.

_________________________________

Plaintiff-Appellant C.D.I.1 appeals from the district court’s decision upholding 

the denial by the Commissioner of Social Security of his application for disability 

insurance benefits and supplemental security income. Exercising jurisdiction under 

* After examining the briefs and appellate record, this panel has determined 

unanimously to honor the parties’ request for a decision on the briefs without oral 

argument. See Fed. R. App. P. 34(f); 10th Cir. R. 34.1(G). The case is therefore 

submitted without oral argument. This order and judgment is not binding precedent, 

except under the doctrines of law of the case, res judicata, and collateral estoppel. It 

may be cited, however, for its persuasive value consistent with Fed. R. App. P. 32.1

and 10th Cir. R. 32.1.

1

 The District of Colorado’s local rules provide that “[a]n order resolving a 

social security appeal on the merits shall identify the plaintiffs by initials only.” 

D.C.COLO.LAPR 5.2(b). We do not have a corresponding rule, but because 

Plaintiff-Appellant docketed this appeal using only his initials, we use that 

convention throughout this Order and Judgment.

FILED

United States Court of Appeals

Tenth Circuit

May 29, 2024

Christopher M. Wolpert

Clerk of Court

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28 U.S.C. § 1291 and 42 U.S.C. § 405(g), we remand for further proceedings 

consistent with this opinion.

I. Facts

C.D.I. filed his application in February 2019. He claimed disability based on 

cirrhosis of the liver, kidney failure, hearing and vision loss, depression, chronic 

fatigue, and back pain.2

 His application was ultimately denied by an ALJ in 

November 2021. The Appeals Council denied C.D.I.’s request for review, thereby 

rendering the ALJ’s November 2021 opinion the final agency decision for purposes 

of judicial review.

A. Evidence Concerning Chronic Fatigue

The evidence concerning C.D.I.’s chronic fatigue consists of three categories. 

First, C.D.I. focuses on symptoms associated with chronic fatigue syndrome (CFS) 

according to Social Security Ruling (SSR) 14-1p, which provides guidance on the 

types of evidence that establish a person has a medically determinable impairment of 

CFS. See SSR 14-1p, 2014 WL 1371245 (Apr. 3, 2014).

3

 In particular, C.D.I. 

consistently complained of low energy, constant headaches, difficulty concentrating, 

2

 C.D.I. alleges he became disabled as a result of multiple conditions. 

Because he only challenges the ALJ’s evaluation of his chronic fatigue, we focus on 

the records relevant to those symptoms and diagnosis.

3

 See Andrade v. Sec’y of Health & Human Servs., 985 F.2d 1045, 1051 

(10th Cir. 1993) (“[S]ocial security rulings do not carry the force and effect of law,” 

but “[t]hey are entitled to deference . . . because they constitute Social Security 

Administration interpretations of its own regulations and the statute which it 

administers.” (citation and internal quotation marks omitted)).

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and fluctuating memory. Id. at *3. He was also diagnosed with CFS by Adrian 

Bickley, a certified physician assistant, in May 2021. In addition, C.D.I. had 

abnormal sleep study findings and was diagnosed with irritable bowel syndrome, 

both of which SSR 14-1p associates with CFS. See id.

Second, C.D.I.’s reports of fatigue are noted throughout the record. For 

example, the medical professionals who treated C.D.I.’s liver cirrhosis mentioned 

fatigue on several occasions. On February 12, 2019, he reported severe fatigue and 

tremor to Karin B. Cesario, M.D., a gastroenterologist. Seven months later in a 

follow-up visit, C.D.I. again reported fatigue, which Dr. Cesario ascribed to C.D.I.’s 

obstructive sleep apnea, psychotropic medications, “and/or beta blockers.” R. vol. 4 

at 1127. Dr. Cesario again noted that C.D.I. had chronic fatigue in March 2020. 

C.D.I also reported fatigue in a visit with a physician assistant in August 2020.

Third, C.D.I. provided testimony at two different hearings concerning the 

limiting effects of his fatigue. In the first hearing, which took place four months 

before PA Bickley’s CFS diagnosis, C.D.I. described having no energy and being 

“wiped out” after doing errands like grocery shopping. R. vol. 9 at 2465. At the 

second hearing, which took place approximately four months after the diagnosis, 

C.D.I. testified that he was constantly tired and that by 2:00 or 3:00 in the afternoon, 

he has to lie down for an hour or two.

B. Administrative Proceedings and District Court Judgment

C.D.I.’s application was denied initially and on reconsideration. After a 

de novo hearing in January 2021, an ALJ denied C.D.I.’s application. The Appeals 

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Council remanded, however, because the ALJ did not evaluate the medical opinions 

of PA Bickley and Chris Bayley, M.D. PA Bickley opined that, based on C.D.I.’s 

“lower back/musculoskeletal pain,” C.D.I. is limited to sitting, standing, or walking 

for less than two hours a day, would need to lie down periodically, and would miss 

more than two days of work per month. R. vol. 8 at 2191. Dr. Bayley submitted a 

statement opining, among other things, that C.D.I.’s mental impairments would 

render him unable to work more than 30 percent of the time.

On remand, the ALJ held a second hearing and again denied C.D.I.’s 

application. The ALJ applied the five-step sequential analysis set forth at 20 C.F.R. 

§ 404.1520(a)(4). The steps include evaluating whether:

(1) the claimant is presently engaged in substantial gainful activity, (2) the 

claimant has a medically severe impairment or impairments, (3) the 

impairment is equivalent to one of the impairments listed in the appendix of 

the relevant disability regulation, (4) the impairment prevents the claimant 

from performing his or her past work, and (5) the claimant possesses a 

residual functional capacity . . . to perform other work in the national 

economy, considering his or her age, education, and work experience.

Allen v. Barnhart, 357 F.3d 1140, 1142 (10th Cir. 2004); see also Trimiar v. Sullivan, 

966 F.2d 1326, 1329 (10th Cir. 1992).

At step two, the ALJ concluded C.D.I. had three medically severe 

impairments: alcoholic cirrhosis of the liver, coronary artery disease, and obesity. 

She did not, however, evaluate C.D.I.’s chronic fatigue. At step five, the ALJ 

concluded C.D.I. had the residual functional capacity to perform a range of light 

work. Again, however, the ALJ’s analysis did not include indications of C.D.I.’s 

chronic fatigue. The ALJ found C.D.I. was not disabled based on her conclusion that 

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there exist jobs in the national economy for an individual with C.D.I.’s age, 

education, work experience, and residual functional capacity.

C.D.I. petitioned for review in the district court, arguing the ALJ improperly 

discounted C.D.I.’s chronic fatigue and should have applied the treating physician rule. 

The district court rejected those arguments and affirmed.

II. Discussion

A. Standard of Review

“We review the district court’s decision de novo and independently determine 

whether the ALJ’s decision is free from legal error and supported by substantial 

evidence.” Fischer-Ross v. Barnhart, 431 F.3d 729, 731 (10th Cir. 2005). 

“Substantial evidence” is “such relevant evidence as a reasonable mind might accept 

as adequate to support a conclusion.” Richardson v. Perales, 402 U.S. 389, 401 

(1971) (internal quotation marks omitted). This “threshold . . . is not high.” Biestek 

v. Berryhill, 139 S. Ct. 1148, 1154 (2019). “Evidence is insubstantial if it is 

overwhelmingly contradicted by other evidence.” O’Dell v. Shalala, 44 F.3d 855, 

858 (10th Cir. 1994).

B. The ALJ’s Evaluation of C.D.I.’s Fatigue Symptoms and CFS

 Diagnosis

C.D.I. contends the ALJ improperly discounted his symptoms of fatigue and 

his diagnosis of CFS.

At the second hearing, C.D.I. identified CFS as one of his severe impairments 

preventing him from any substantial gainful activity, and he provided testimony 

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about the effects of fatigue on his daily life. C.D.I. argues that “the ALJ erroneously 

concluded that C.D.I.’s chronic fatigue syndrome was not a medically determinable 

impairment and did not discuss SSR 14-[1]p.” Reply Br. at 5. As far as we have 

been able to determine, however, the ALJ’s step-two evaluation contains no mention 

of CFS at all, much less an analysis of whether it constitutes a medically 

determinable impairment. Although the ALJ mentioned the word “fatigue” once in 

the context of C.D.I.’s possible stroke, it appeared to refer to fatigue generally as a 

symptom of stroke, not as a symptom specifically experienced by C.D.I. Having 

omitted any discussion of CFS, it is therefore not surprising that the ALJ’s decision 

contains no mention of SSR 14-1p.

The failure to consider all of the claimant’s medically determinable 

impairments, singly and in combination, is typically reversible error. Salazar v. 

Barnhart, 468 F.3d 615, 621 (10th Cir. 2006). But because the ALJ found other 

severe impairments—namely, cirrhosis of the liver, coronary artery disease, and 

obesity—the error is harmless. See Allman v. Colvin, 813 F.3d 1326, 1330 (10th Cir. 

2016) (“[T]he failure to find a particular impairment severe at step two is not 

reversible error when the ALJ finds that at least one other impairment is severe.”). 

The ALJ’s step five analysis, however, was also problematic. An ALJ must 

consider “all of the relevant medical and other evidence” in assessing a claimant’s 

residual functional capacity. 20 C.F.R. § 404.1545(a)(3). This means, as the 

Commissioner notes, that “[t]he ALJ accordingly considers a claimant’s subjective 

symptoms against the backdrop of the other record evidence.” Answer Br. at 24; see 

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also 20 C.F.R. § 404.1529(c)(4). Here, the backdrop against which the ALJ 

considered C.D.I.’s fatigue symptoms was incomplete. First, the ALJ failed to 

acknowledge the CFS diagnosis, and indeed discounted C.D.I.’s reports of fatigue 

based on the purported lack of any supporting clinical findings or other medical 

evidence. See R. vol. 11 at 2853 (rejecting C.D.I.’s reports of fatigue because they 

“are subjective and cannot be verified by . . . clinical findings” (emphasis added)); 

see also id. at 2851 (finding that C.D.I.’s statements concerning the limiting effects 

of his fatigue “are not entirely consistent with the medical evidence”).

Second, there was evidence in the record of other symptoms, diagnoses, and 

laboratory findings that SSR 14-1p associates with CFS. These included low energy, 

consistent headaches, difficulty concentrating, fluctuating memory, irritable bowel 

syndrome, and abnormal sleep study findings. See SSR 14-1p, 2014 WL 1371245, 

at *3. The ALJ determined that the evidence of headaches was unclear from the 

record, but her step five analysis contains virtually no discussion of the remaining 

indications of CFS. The Commissioner surmises that the ALJ did not discuss SSR 

14-1p because CFS is a diagnosis of exclusion—i.e., a diagnosis made by process of 

elimination once all other options are exhausted—and there was evidence of other 

conditions linked to C.D.I.’s reported fatigue. Embracing this reasoning, however, 

“risks violating the general rule against post hoc justification of administrative 

action.” Allen, 357 F.3d at 1145.

It is true the ALJ found PA Bickley’s August 2020 opinion was unsupported 

by the record or a narrative explanation. But that opinion was based on C.D.I.’s 

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lower back and musculoskeletal pain, not fatigue, and PA Bickley signed the opinion 

nine months before he diagnosed C.D.I. with chronic fatigue syndrome. Thus, the 

ALJ’s opinion gives no indication that the step five analysis included consideration 

of PA Bickley’s diagnosis. The district court opined that the ALJ “did not call into 

question [PA Bickley’s] diagnosis or any other diagnosis.” R. vol. 11 at 2896. This 

is true, but only insofar as the ALJ did not acknowledge the diagnosis at all. Indeed, 

the phrase “chronic fatigue syndrome” appears nowhere in the ALJ’s decision.

“It is improper for the ALJ to pick and choose among medical reports, using 

portions of the evidence favorable to [her] position while ignoring other evidence.” 

Hardman v. Barnhart, 362 F.3d 676, 681 (10th Cir. 2004); see also SSR 96-8p, 

1996 WL 374184, at *7 (July 2, 1996) (the assessment of residual functional capacity 

“must . . . [i]nclude a resolution of any inconsistencies in the evidence as a whole”). 

We hold that the ALJ’s RFC determination at step five was not based on “all of the 

relevant medical and other evidence,” 20 C.F.R. § 404.1545(a)(3), and we therefore 

remand for the ALJ to consider whether C.D.I. possesses a residual functional capacity 

to perform other work in the national economy in light of all the relevant medical and 

other evidence, including the CFS diagnosis and other evidence relating to CFS.

C. Treating Physician Rule

C.D.I. also contends the ALJ erred in failing to apply the treating physician 

rule, which was adopted by regulation in 1991 and directed the Commissioner to

“give more weight to medical opinions from treating sources than those from 

non-treating sources,” Langley v. Barnhart, 373 F.3d 1116, 1119 (10th Cir. 2004). 

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Under regulations adopted in 2017, however, the treating physician rule was 

abandoned. See Austin v. Kijakazi, 52 F.4th 723, 730 (8th Cir. 2022) (noting that 

under the revised regulations, “the now-defunct treating physician rule . . . no longer 

applies”). The new regulations, which apply here because C.D.I. filed his application 

in 2019, provide that the ALJ does “not defer or give any specific evidentiary weight, 

including controlling weight, to any medical opinion(s) . . . including those from [the 

claimant’s] medical sources.” 20 C.F.R. §§ 404.1520c(a), 416.920c(a). Instead, the 

ALJ evaluates them based on their persuasiveness. See id. §§ 404.1520c(c), 

416.920c(c). 

C.D.I. nonetheless argues the ALJ should have applied the former rule 

because (1) the Social Security Act mandates the treating physician rule and the 

Commissioner lacks the authority to abrogate it, and (2) the 2017 regulation is an 

improper attempt to overturn our adoption of the rule in Broadbent v. Harris, 

698 F.2d 407, 412 (10th Cir. 1983). We reject the argument. 

“Where . . . the statute expressly entrusts the [Commissioner] with the 

responsibility for implementing a provision by regulation, our review is limited to 

determining whether the regulation[] promulgated exceeded the [Commissioner’s] 

statutory authority and whether [it is] arbitrary and capricious.”4

 Heckler v. 

4

 C.D.I. does not contend that the 2017 regulations are arbitrary and 

capricious, and, in any case, the Commissioner has adequately explained the reasons 

for the new rule. See Revisions to Rules Regarding the Evaluation of Medical 

Evidence, 82 Fed. Reg. 5844, 5853 (Jan. 18, 2017) (to be codified at 20 C.F.R. Parts 

404 and 416) (explaining the new regulations give more consideration to the content 

of the evidence, and “better reflect[] the actual state of health care today,” in which 

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Campbell, 461 U.S. 458, 466 (1983). Here, the Commissioner did not exceed her 

statutory authority because the 2017 rule change falls squarely within the Social 

Security Act’s express delegation of authority to the Commissioner. The Act gives 

“exceptionally broad authority” to the Commissioner “to prescribe standards for 

applying certain sections of the . . . Act.” Id. (internal quotation marks omitted). 

This includes “full power and authority to . . . adopt reasonable and proper rules and 

regulations to regulate and provide for the nature and extent of the proofs and 

evidence and the method of taking and furnishing the same” for adjudicating 

disability claims. 42 U.S.C. § 405(a). As the district court correctly pointed out, the 

new regulations only concern how an ALJ should consider medical evidence; they do 

not change the “substantial evidence” standard of review or alter this court’s 

obligation to review administrative decisions to determine whether they are 

supported by substantial evidence.

The fact that this court adopted the treating physician rule before the 

Commissioner codified it in 1991 is of no consequence. “A court’s prior judicial 

construction of a statute trumps an agency construction otherwise entitled to Chevron 

deference only if the prior court decision holds that its construction follows from the 

unambiguous terms of the statute and thus leaves no room for agency discretion.” 

Nat’l Cable & Telecomms. Ass’n v. Brand X Internet Servs., 545 U.S. 967, 982 

patients more commonly receive health care from multiple medical sources, such as 

managed care organizations, instead of from a single physician).

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(2005).

5

 We have never held that the Social Security Act requires, unambiguously or 

otherwise, the application of the treating physician rule. See Harner v. Soc. Sec. 

Admin., 38 F.4th 892, 898 (11th Cir. 2022) (“none of the courts of appeals that 

applied the treating-physician rule before the 1991 regulation held that the rule was 

required by the Act”). Because the Social Security Act does not unambiguously 

require application of the treating physician rule, our adoption of the rule in

Broadbent, 698 F.2d at 412, does not trump the 2017 regulations.

On remand, the ALJ should evaluate the medical opinions, including 

PA Bickley’s medical opinion, based on their persuasiveness, as directed by the 

regulations adopted in 2017.

III. Conclusion

We remand to the ALJ for the reasons discussed above.

Entered for the Court

Allison H. Eid

Circuit Judge

5

 See Chevron U.S.A, Inc., v. Nat. Res. Def. Council, Inc., 467 U.S. 837 

(1984).

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