What is the composite scoring system called that combines both the intensity of immunohistochemical staining and the percentage of positive cells into a single numerical value to quantify protein expression in a tumor sample?

• A. IHC-Score
• B. Quick-score
• C. H-score
• D. Allred score

Answer: (C)

In this scoring approach, the goal is to quantify protein expression with a single number by incorporating both how intense the staining is and how many cells show staining. The H-score does this by performing a weighted sum across staining intensities. For each intensity category (0 = no staining, 1 = weak, 2 = moderate, 3 = strong), you determine the percentage of tumor cells in that category, multiply that percentage by the intensity value, and add all the products together. The final value ranges from 0 to 300, with higher numbers indicating more widespread and stronger expression.

For example, if 50% of cells stain strongly (3), 30% are moderately stained (2), and 20% are weakly stained (1), the H-score is (50×3) + (30×2) + (20×1) = 150 + 60 + 20 = 230.

Allred score, in contrast, combines proportion and intensity into two components that are added to yield a smaller range (0–8), while Quick-score is often described as a product of overall intensity and percentage in a simpler form. The H-score is the standard name for the single numeric value that integrates the full distribution of staining intensities across cells.