FY 2027 MEDESUN®
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Section III · FY 2027

Reporting additional diagnoses — Section III

What makes a secondary condition reportable, when a previous condition should be left off, and why an abnormal laboratory value is not by itself a diagnosis.

Dr. Santosh Kumar Guptha, CCS, CPC, COC, CIC, CRC, CPMA, CDIP, CPCO — AHIMA-Approved ICD-10-CM/PCS Trainer, MEDESUN® Medical Coding Academy Guidelines effective October 1, 2026 – September 30, 2027

An additional diagnosis is reportable when it is a clinically significant condition that affects patient care by requiring any one of five things: clinical evaluation; therapeutic treatment; diagnostic procedures; extended length of hospital stay; or increased nursing care and/or monitoring. One is enough.

Section III — may this condition be reported as an additional ("other") diagnosis?ClinicalevaluationTherapeutictreatmentDiagnosticproceduresExtended lengthof stayIncreased nursingcare or monitoringAny ONE of the five is enoughAbnormal findingsnot coded unless the provider states the clinical significanceResolved conditions from an earlier admissionnot reported — but Z80–Z87 history codes may be used
Section III — the five criteria for an additional diagnosis

UHDDS item 11-b defines other diagnoses as all conditions that coexist at the time of admission, that develop subsequently, or that affect the treatment received and/or the length of stay. Diagnoses that relate to an earlier episode which have no bearing on the current hospital stay are to be excluded. The UHDDS definitions apply to inpatients in acute care, short-term, long term care and psychiatric hospital settings, and have since been extended to all non-outpatient settings including home health agencies, rehabilitation facilities and nursing homes, and to hospice services at all levels of care.

The three specific rules#

RuleWhat to do
APrevious conditionsIf the provider has included a diagnosis in the final diagnostic statement — the discharge summary or the face sheet — it should ordinarily be coded. NEVER Resolved conditions and status-post procedures from previous admissions that have no bearing on the current stay are not reported, and are coded only if required by hospital policy. ALWAYS History codes Z80–Z87 may be used as secondary codes where the historical or family history condition has an impact on current care or influences treatment
BAbnormal findingsNEVER Abnormal laboratory, x-ray, pathologic and other diagnostic results are not coded and reported unless the provider indicates their clinical significance. If the findings are outside the normal range and the provider has ordered other tests to evaluate the condition or prescribed treatment, it is appropriate to ask the provider whether the abnormal finding should be added. EXCEPTION This differs from outpatient practice for encounters for diagnostic tests interpreted by a provider — see Section IV.K
CUncertain diagnosisA diagnosis qualified at discharge as probable, suspected, likely, questionable, possible, still to be ruled out, compatible with, consistent with, or similar terms, is coded as if it existed or was established, on the basis of the diagnostic workup, arrangements for further workup or observation, and the initial therapeutic approach. EXCEPTION Applicable only to inpatient admissions to short-term, acute, long-term care and psychiatric hospitals
The five criteria — any one is sufficient
Clinical evaluationThe condition was assessed
Therapeutic treatmentSomething was done about it
Diagnostic proceduresTests were performed to investigate it
Extended length of hospital stayIt kept the patient in longer
Increased nursing care and/or monitoringIt changed the level of care required

Practice questions#

Q1A serum potassium of 2.9 mmol/L is recorded. The provider does not mention hypokalaemia anywhere in the record, but potassium replacement is ordered. What should the coder do?

  1. AAssign the hypokalaemia code based on the laboratory value
  2. BAssign nothing and take no further action
  3. CAsk the provider whether the abnormal finding should be added
  4. DAssign an unspecified electrolyte disorder code
Show answer & rationale

Correct answer: C. Ask the provider whether the abnormal finding should be added

Rationale. Section III.B states that abnormal findings are not coded and reported unless the provider indicates their clinical significance, and that if the findings are outside the normal range and the provider has ordered other tests to evaluate the condition or prescribed treatment, it is appropriate to ask the provider whether the abnormal finding should be added. Assigning the code from the laboratory value alone would breach Section I.A.19 as well, which bases code assignment on the provider's diagnostic statement.

Q2How many of the five criteria must a condition meet to be reported as an additional diagnosis?

  1. AAll five
  2. BAt least three
  3. CAt least one
  4. DAt least two
Show answer & rationale

Correct answer: C. At least one

Rationale. Section III defines other diagnoses as additional clinically significant conditions that affect patient care in terms of requiring clinical evaluation; or therapeutic treatment; or diagnostic procedures; or extended length of hospital stay; or increased nursing care and/or monitoring. The criteria are joined by 'or', so any one is sufficient.

Q3A discharge summary lists a resolved condition from an admission two years ago that had no bearing on the current stay. What does Section III direct?

  1. ACode it, because it appears in the final diagnostic statement
  2. BDo not report it; it is coded only if required by hospital policy
  3. CCode it with a history code only
  4. DQuery the provider before deciding
Show answer & rationale

Correct answer: B. Do not report it; it is coded only if required by hospital policy

Rationale. Section III.A states that some providers include in the diagnostic statement resolved conditions or diagnoses and status-post procedures from previous admissions that have no bearing on the current stay, and that such conditions are not to be reported and are coded only if required by hospital policy. The same guideline permits history codes Z80-Z87 as secondary codes where the historical condition has an impact on current care or influences treatment.

Q4An inpatient discharge summary documents “probable urinary tract infection” with antibiotics started and cultures pending. How is it reported?

  1. ADo not code it
  2. BCode the symptoms only
  3. CCode the urinary tract infection as if it existed or was established
  4. DCode it only if the culture later returns positive
Show answer & rationale

Correct answer: C. Code the urinary tract infection as if it existed or was established

Rationale. Section III.C states that if the diagnosis documented at the time of discharge is qualified as probable, suspected, likely, questionable, possible, still to be ruled out, compatible with, consistent with, or other similar terms indicating uncertainty, the condition is coded as if it existed or was established — the bases being the diagnostic workup, arrangements for further workup or observation, and the initial therapeutic approach. The guideline is applicable only to inpatient admissions to short-term, acute, long-term care and psychiatric hospitals.

Q5Which criterion for reporting additional diagnoses appears in the newborn guidelines but not in Section III?

  1. AIncreased nursing care and/or monitoring
  2. BExtended length of hospital stay
  3. CHas implications for future health care needs
  4. DClinical evaluation
Show answer & rationale

Correct answer: C. Has implications for future health care needs

Rationale. Section I.C.16.a.6 lists the six criteria for clinically significant newborn conditions and notes explicitly that the perinatal guidelines are the same as the general coding guidelines for additional diagnoses except for the final point regarding implications for future health care needs. Section I.C.16.c.2 adds that this guideline should not be used for adult patients.

Scenarios#

Scenario 1A chronic condition that was monitored but not treated

An inpatient admitted for pneumonia has well-controlled hypothyroidism. Levothyroxine is continued during the stay, thyroid function is checked once, and the condition appears on the discharge summary.

Show coded answer & rationale
SeqCodeDescription
1Pneumoniathe applicable pneumonia code — principal diagnosis
2E03.9Hypothyroidism, unspecified — reportable as an additional diagnosis

Rationale. Section III defines other diagnoses as conditions that affect patient care by requiring any of clinical evaluation, therapeutic treatment, diagnostic procedures, extended length of stay, or increased nursing care and monitoring. Continuing levothyroxine is therapeutic treatment and the thyroid function test is a diagnostic procedure, so at least two criteria are met. Section III.A supports coding a diagnosis the provider included in the final diagnostic statement, because this one does bear on the current stay.

Guideline: Section III, III.A

Scenario 2An incidental finding on imaging

A chest radiograph performed for pneumonia incidentally shows a small pulmonary nodule. The radiologist recommends follow-up imaging in six months. The attending physician does not mention the nodule anywhere in the record and orders nothing for it during the stay.

Show coded answer & rationale
SeqCodeDescription
1Pneumoniathe applicable pneumonia code — principal diagnosis
2—no code for the nodule unless the provider indicates its clinical significance

Rationale. Section III.B states that abnormal findings, including x-ray results, are not coded and reported unless the provider indicates their clinical significance. A radiologist's recommendation is not the attending provider's statement of clinical significance, and nothing was evaluated or treated during this stay. Where the finding is outside the normal range and the provider has ordered other tests or prescribed treatment, the guideline directs asking the provider — here neither happened during the admission.

Guideline: Section III.B

Scenario 3The same case in an outpatient setting

The identical pulmonary nodule is found on an outpatient chest radiograph. The radiologist interprets the film and the final report, which states the nodule as a definitive finding, is available at the time of coding.

Show coded answer & rationale
SeqCodeDescription
1Reason for the testthe sign, symptom or condition that prompted the radiograph, if a definitive diagnosis was not established
2R91.1Solitary pulmonary nodule — the confirmed finding documented in the interpretation

Rationale. Section IV.K states that for outpatient encounters for diagnostic tests that have been interpreted by a physician, where the final report is available at the time of coding, any confirmed or definitive diagnosis documented in the interpretation is coded, and related signs and symptoms are not coded as additional diagnoses. Section III.B notes explicitly that this differs from the inpatient coding practice for abnormal findings. The setting, not the finding, changes the answer.

Guideline: Section IV.K; Section III.B

Primary sources#