Highest LAP score is seen in -
High levels of LAP score are found in:

Infection
Inflammatory disorder
Growth factor therapy
Pregnancy
OCP
Stress
Myeloproliferative disorders (except CML)
Drugs (e.g. Lithium, Corticosteroid, Estrogen)

Abnormally high values of LAP is seen in myeloproliferative disorder e.g. polycythemia vera and myelofibrosis
Decreased LAP score is seen in CML (chronic phase) and PNH (paroxysmal nocturnal hemoglobinuria).
CML
Polycythemia vera
PNH
Pregnancy