PMR Blood Tests Explained: ESR, CRP, and More

TL;DR: There’s no single blood test that proves PMR. Doctors look at the pattern: your story and exam plus inflammation tests (ESR/CRP). Other tests help rule out look-alike problems and set a safe baseline before treatment. A small group of people with clear PMR can have near-normal inflammatory markers — so your whole picture matters.

ESR (Erythrocyte Sedimentation Rate)

• What it is: a general inflammation test. Higher numbers suggest more inflammation.
• In PMR: ESR is often high, but it can be normal in a minority (reports range from ~1–22%). Doctors interpret ESR with your symptoms and other labs.

CRP (C-Reactive Protein)

• What it is: another inflammation marker that tends to rise quickly.
• In PMR: CRP is often raised at diagnosis and helpful for tracking your response to treatment over time. If ESR is normal but CRP is high, PMR can still be present.

CBC (Complete Blood Count)

• Why it’s checked: looks for anemia, infection clues, and platelet changes that can go along with inflammation.
• What it tells us: helps rule out other causes of pain and fatigue and gives a baseline before steroids.

CMP (Chemistry panel: kidneys, liver, glucose, electrolytes)

• Why it’s checked: steroids can affect blood sugar and blood pressure; some add-on medicines need liver and kidney monitoring.
• What it tells us: safe starting point, and a way to catch problems early.

CK (Creatine Kinase)

• Why it’s checked: muscle-damage test.
• Why it matters in PMR: CK is usually normal in PMR (because PMR is about stiffness and inflammation around joints, not muscle injury). High CK may point to other muscle diseases or drug effects (e.g., statins).

TSH (Thyroid-Stimulating Hormone)

• Why it’s checked: thyroid problems, especially low thyroid, can mimic PMR symptoms (aches, fatigue, stiffness).
• What it tells us: helps rule out a common look-alike.

Other tests your doctor may order

• Rheumatoid factor (RF) and anti-CCP/ACPA to evaluate for rheumatoid arthritis.
• Protein electrophoresis or urinalysis if the story doesn’t fit.
• Vitamin D or bone profile to plan bone protection on steroids. Your local pathway may add items like U&E, LFTs, and plasma viscosity.

How we use these tests together

• Diagnosis: ESR/CRP support the story; other labs rule out mimics.
• Monitoring: we follow your symptoms + ESR/CRP over time to guide tapering and catch flares early.