Cytochemical Stains in Haematology
Iffat Jamal · Journal of Evidence Based Medicine and Healthcare · 2020
LAP is present in the cytoplasm of neutrophils, eosinophils, osteoblasts, B lymphocytes and endothelial cells. This activity can be quantified by scoring from 0 to 4+ based on the intensity of the staining. The cell that doesn’t stain is given a score of zero and that has strong staining is given a score of 4. The total score is calculated counting the individual score of 100 neutrophils or bands. Normal LAP score ranges from 15 to 130. Purpose Helps in differentiating Chronic myeloid Leukemia from leukemoid reaction as both show a left shift with increased precursors. While leukemoid reaction will show increased LAP score, it is very low in CML. Principle Alkaline phosphatase activity is present in varying degrees in the neutrophil and band form of the granulocytes. Interpretation Count 100 neutrophils and score them (0 to +4), then calculate the final score by adding the total scores. Grading Score 0- no stain, 1+means faint staining, 2+ means moderate staining, 3+ means strong staining with cytoplasmic background, 4+ means strong staining without cytoplasmic background. Normal Range: 15-130