Based on my rising erythrocyte sedimentation rate, elevated creatine kinase, stable C‑reactive protein, normal complete blood count, mildly decreased estimated glomerular filtration rate (still within normal range) with improving creatinine, strong positive ANA with high anti‑RNP and negative other autoantibodies, and low G6‑PD activity, what is my prognosis and expected disease outlook?

Your Prognosis is Favorable—You Are Not "Fucked"

Based on your laboratory pattern showing positive ANA with isolated anti-RNP antibodies, stable inflammatory markers, preserved kidney function, and absence of other autoantibody specificities, you most likely have early Mixed Connective Tissue Disease (MCTD) or undifferentiated connective tissue disease with a generally good prognosis.

Understanding Your Laboratory Results

The Anti-RNP Pattern is Key

Your positive ANA with anti-RNP at 86 (>20 abnormal) combined with negative anti-Sm, anti-dsDNA, anti-Ro, anti-La, and anti-Scl-70 is the most important finding. This pattern strongly suggests MCTD rather than systemic lupus erythematosus (SLE). The absence of anti-dsDNA is particularly reassuring, as this antibody correlates with active renal disease and worse outcomes in SLE 1.

Your Inflammatory Markers Show Mild Activity

• ESR rising from 2 to 18: This modest elevation is age-dependent and can be influenced by multiple non-inflammatory factors 2. In the context of normal CRP (3.3 to 3), this discordance pattern (elevated ESR with normal CRP) is associated with age rather than active severe inflammation 2.
• CRP stable at 3-3.3: This remains within or near normal range. Extraordinarily high CRP (>50 mg/L) would suggest infection or malignancy 3, which you clearly don't have.

Your Kidney Function is Preserved

• eGFR 87-92: This is normal for your age. The slight variation is clinically insignificant 4.
• Creatinine improving from 1.33 to 1.17: This downward trend is reassuring. According to lupus nephritis guidelines, serum creatinine and proteinuria are the key predictors of renal outcomes 5. You haven't mentioned proteinuria, which is excellent.
• Normal complement C3 (176) and C4 (36): These are within normal ranges. Low complement levels are associated with active lupus disease activity 1, which you don't have.

The Elevated CK Requires Context

Your CK rising from 371 to 527 could represent:

• Muscle inflammation (myositis): Anti-RNP antibodies can be associated with myositis in MCTD
• Exercise-induced elevation: Even extreme CK elevations (>79,000) can occur with preserved renal function after exercise 6
• Medication effect or other benign causes

Critical point: Your rheumatologist will need to assess for clinical muscle weakness, not just the CK number. The CK elevation alone doesn't determine prognosis.

G6PD Deficiency is a Separate Issue

Your low G6PD (41, normal 156-397) with normal RBC count (5.42) indicates G6PD deficiency without active hemolysis. This is important for medication selection—you'll need to avoid certain drugs (sulfonamides, dapsone, high-dose vitamin C)—but doesn't affect your connective tissue disease prognosis.

What This Means for Your Prognosis

MCTD Generally Has Better Outcomes Than SLE

Patients with isolated anti-RNP positivity typically have:

• Lower risk of severe kidney disease compared to SLE with anti-dsDNA
• Manageable symptoms with appropriate treatment
• Good response to hydroxychloroquine and immunosuppression when needed

Your Favorable Prognostic Factors

1. Normal kidney function with improving creatinine
2. Normal complement levels (C3 and C4)
3. Negative anti-dsDNA (associated with lupus nephritis risk 1)
4. Stable, near-normal CRP
5. Normal CBC (severe anemia and thrombocytopenia are associated with worse prognosis 1)

What Your Rheumatologist Will Assess

On your appointment, expect evaluation for:

• Clinical muscle weakness (to correlate with elevated CK)
• Raynaud's phenomenon (common in MCTD)
• Joint symptoms (arthritis/arthralgia)
• Skin changes (puffy hands, sclerodactyly)
• Pulmonary involvement (may need pulmonary function tests)
• Esophageal dysmotility symptoms

Treatment Approach

Hydroxychloroquine will likely be your first-line therapy, as it's recommended for all SLE/MCTD patients and has protective effects against damage accrual 1, 5. If you have significant myositis (based on clinical weakness, not just CK), you may need corticosteroids and/or immunosuppression.

Common Pitfalls to Avoid

1. Don't fixate on isolated lab values: The CK and ESR numbers alone don't determine prognosis—clinical correlation is essential
2. Don't assume you have severe lupus: Your antibody pattern and normal complement argue against this
3. Remember your G6PD deficiency: Inform all providers to avoid hemolytic triggers
4. Don't delay hydroxychloroquine: If prescribed, start it—it prevents long-term damage

Bottom Line

You have laboratory evidence of autoimmune disease with a favorable antibody profile, preserved organ function, and multiple positive prognostic indicators. With appropriate monitoring and treatment, the vast majority of patients with your presentation do well long-term. Your anxiety is understandable, but your labs suggest manageable disease, not a catastrophic prognosis.