CRM: Clinical Reasoning Model
A fine-tuned small language model trained on 511 physician-annotated clinical cases. Walks through differential diagnosis step by step — with fewer hallucinations than the base model.
Why did I do this? Because I initially used the base model and found it was too dumb to understand medical terminology. This made it say stupid stuff. So, I learned how to fine-tune it. This means I just took the already completed model and taught it further using the DiReCT dataset. I used that dataset because it was free and easily accessible. Admittedly, it is a small dataset, as far as fine-tuning goes - but it worked for my purposes. The data below shows the result of this fine-tuning: it understood medical terminology much better, and was able to actually function inside the AUC app like I wanted. Reasonably well at least. It's still only a 3 billion parameter model, so its still suboptimal.
Below is a test case example to show how it improved:
Training Overview
Test Case
Model Outputs — Side by Side
Base Llama 3.2 3B (no fine-tuning)
Step 1: The primary complaint is related to the endocrine system. Step 2: Fatigue can be caused by anemia or hypothyroidism... but in most cases it is due to iron deficiency anaemia... Step 3: Weight loss may occur if there was significant reduction in appetite... Step 4: Cold intolerance occurs when your body produces too much thyroxine hormone; you feel hot even after being indoors... Step 5: Constipation could result from low estrogen, medications, poor diet, dehydration, stress and anxiety... Potential diagnosis: HypoThyroidism. Further testing required.
Fine-tuned model (ploppy2/Clinical-Reasoning-Test1)
Step 1: The most likely underlying cause is hypothyroidism. The primary symptom that led to this conclusion was cold intolerance, which suggests decreased thyroid hormone production. Step 2: There may be an autoimmune process involved — Hashimoto's disease is a common cause of hypothyroidism. Step 3: Thyroid function tests will confirm whether she suffers from low TSH levels indicating underactive thyroid gland. Step 4: If confirmed by lab testing, treatment should start immediately. Options include synthetic replacement medication (levothyroxine) daily.
What Changed
Base model problems
- States cold intolerance = too much thyroid hormone (factually wrong)
- Claims weight loss occurs (wrong — hypothyroidism causes weight gain)
- TSH description devolves into unrelated topics (bone health, memory, immunity)
- Disorganized and clinically unfocused
Fine-tuned model improvements
- Correctly identifies hypothyroidism from symptom pattern
- Appropriately mentions Hashimoto's as autoimmune cause
- Logical flow: symptoms → diagnosis → testing → treatment
- Stays clinically relevant throughout
Conclusion
Potential Next Steps
- Expand training data beyond 511 cases for broader clinical coverage
- Upgrade to Llama 3.2 8B with a more powerful GPU for better baseline capability
- Clean up training data to reduce disclaimer and hedging language in outputs
- Evaluate systematically across a held-out test set of cases