TABLE 1

Four-Point IRS Classification

IRSPercentage of positive cellsIntensity of staining= IRS (0–12)
0 = negative0 = no positive cells0 = no color reaction0–1 = negative
1 = mild1 = <10% positive cells1 = mild reaction2–3 = mild
2 = moderate2 = 10%–50% positive cells2 = moderate reaction4–8 = moderate
3 = strong3 = 51%–80% positive cells3 = intense reaction9–12 = strongly positive
4 = >80% positive cells

  • Modified from Kaemmerer et al. (15)