What are the key laboratory findings in patients with microscopic polyangiitis?

In patients with microscopic polyangiitis, a key laboratory finding is the presence of elevated erythrocyte sedimentation rate (ESR) and positivity for perinuclear anti-neutrophil cytoplasmic antibodies (P-ANCA).

Elevated ESR reflects systemic inflammation, which is characteristic of vasculitis conditions like microscopic polyangiitis. This increased inflammatory response indicates the presence of an underlying disease process.

P-ANCA positivity specifically helps in diagnosing microscopic polyangiitis, as it is associated with this condition and some other forms of small vessel vasculitis. The detection of P-ANCA antibodies, particularly myeloperoxidase-ANCA (MPO-ANCA), is useful in identifying and confirming the diagnosis of this disease.

The other options do not accurately reflect the typical laboratory findings in microscopic polyangiitis. While high blood glucose and low hemoglobin, low platelet count with hypereosinophilia, or normal creatinine with high electrolytes may indicate different medical conditions or laboratory anomalies, they do not align with the hallmark findings seen in this specific type of vasculitis. Thus, the combination of elevated ESR and P-ANCA positivity stands out as the most relevant and critical laboratory indication for this