Synthetic data only. Never enter patient information; nothing is sent or stored. For clinicians. Not FDA cleared.

CPE-001 · synthetic case FX-008

Low FT4 with inappropriately mild TSH elevation and pituitary history

Pituitary history. FT4 is low and TSH is only slightly high.

Synthetic · no real patientReviewed acceptance scenarioThyroid engine v1.1.0

Purpose: Prevent missed central dysfunction when TSH is not low.

Inputs the engine received

Patient

Age and sex
46, male

Context

Known pituitary or hypothalamic disease
Yes

Symptoms

Fatigue
Present

Laboratory

TSH
5.2 mIU/L (ref 0.4–4.5)
FT4
0.5 ng/dL (ref 0.8–1.8)

What the engine reports

Detected clinical pattern

Possible Central Hypothyroidism Pattern — Safety Review Required

FT4 is low with TSH not appropriately elevated for the degree of low FT4; pituitary/hypothalamic context and adrenal safety must be assessed.

  • Etiology / context: Pituitary/Hypothalamic Cause Possible

Why this pattern was identified

  • TSH not appropriately elevated for low FT4. FT4 0.5 ng/dL (ref 0.8–1.8) with only mildly elevated TSH 5.2 mIU/L (ref 0.4–4.5) in a patient with pituitary/hypothalamic context.

Recommended next steps

For physician consideration. Urgent review always comes first.

  1. 1Assess morning cortisol/ACTH and adrenal safety before thyroid hormone replacement in suspected central disease.
  2. 2Evaluate additional pituitary axes as clinically appropriate (gonadal, adrenal, growth hormone, prolactin).
  3. 3Consider pituitary MRI when pituitary disease is suspected or supported by the clinical context.
Evidence and rule trace · 1 rules

PR-HT-03Possible Central Hypothyroidism Pattern

Inputs: FT4 0.5 ng/dL (ref 0.8–1.8) · TSH 5.2 mIU/L (ref 0.4–4.5) · Pituitary/hypothalamic context documented

Low FT4 with TSH not appropriately elevated for the degree of low FT4.

Evidence

  • EV-ENDO-HYPOPIT-2016 · Fleseriu M et al. Hormonal Replacement in Hypopituitarism in Adults. J Clin Endocrinol Metab. 2016;101(11):3888-3921.

Physician adjudication required. For clinician review only. This output identifies clinical patterns and safety considerations from the documented inputs. It does not establish an autonomous diagnosis or treatment plan. Physician confirmation is required.

Change the values

The same engine, starting from this case. Change any value and watch the pattern and the rule trace react.

Thyroid-function testsMove the sliders or type values
  • below range
  • within range
  • above range
  • below range
  • within range
  • above range
TSH5.2 mIU/L · above reference
ref 0.44.5
Free T40.5 ng/dL · below reference
ref 0.81.8
Where this sits on the TSH × FT4 plane
Overt primarySubclinicalDiscordantCentral?EuthyroidDiscordantCentral?Low TSHThyrotoxicTSH ↑FT4 →

Zones are drawn from your reference intervals. The engine, not the map, decides the pattern.

Laboratory values and reference rangesUse your lab's own interval
Ref. low
Ref. high

µIU/mL and mIU/L are numerically identical.

Ref. low
Ref. high
Ref. low
Ref. high

Interpreted against the reporting assay's upper limit.

Ref. low
Ref. high

Only used in the thyrotoxicosis pathway.

Ref. low
Ref. high
Ref. low
Ref. high
Ref. low
Ref. high
Ref. low
Ref. high
Patient context
Sex at birth
Medications and exposures
Symptoms and physical findingsSupportive only: never classify on their own

Symptoms

Signs and decompensation red flags

Live result · computed in your browser

Detected clinical pattern

Possible Central Hypothyroidism Pattern — Safety Review Required

FT4 is low with TSH not appropriately elevated for the degree of low FT4; pituitary/hypothalamic context and adrenal safety must be assessed.

  • Etiology / context: Pituitary/Hypothalamic Cause Possible

Why this pattern was identified

  • TSH not appropriately elevated for low FT4. FT4 0.5 ng/dL (ref 0.8–1.8) with only mildly elevated TSH 5.2 mIU/L (ref 0.4–4.5) in a patient with pituitary/hypothalamic context.

Recommended next steps

For physician consideration. Urgent review always comes first.

  1. 1Assess morning cortisol/ACTH and adrenal safety before thyroid hormone replacement in suspected central disease.
  2. 2Evaluate additional pituitary axes as clinically appropriate (gonadal, adrenal, growth hormone, prolactin).
  3. 3Consider pituitary MRI when pituitary disease is suspected or supported by the clinical context.
Evidence and rule trace · 1 rules

PR-HT-03Possible Central Hypothyroidism Pattern

Inputs: FT4 0.5 ng/dL (ref 0.8–1.8) · TSH 5.2 mIU/L (ref 0.4–4.5) · Pituitary/hypothalamic context documented

Low FT4 with TSH not appropriately elevated for the degree of low FT4.

Evidence

  • EV-ENDO-HYPOPIT-2016 · Fleseriu M et al. Hormonal Replacement in Hypopituitarism in Adults. J Clin Endocrinol Metab. 2016;101(11):3888-3921.

Physician adjudication required. For clinician review only. This output identifies clinical patterns and safety considerations from the documented inputs. It does not establish an autonomous diagnosis or treatment plan. Physician confirmation is required.

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