Elevated Sm accumulation is defined as 4 to 6 times normal SM accumulation and normal enzyme activity. Niemaoh-Pick disease (NPD) is also known as sphingomyelin lipidosis, so how is elevated SM accumulation diagnosed? Here we will take a look. The diagnosis of elevated sm accumulation 1. hepatosplenomegaly. 2, with or without neurological damage or cherry erythema in the fundus of the eye. 3, peripheral blood lymphocytes and monocytes plasma with vacuoles. 4, Foam cells can be found in bone marrow. 5.X-ray lung shows corn-like or reticular infiltration. 6, conditions can be neurosphingolipase activity assay, quiet neurosphingolipid excretion, liver, spleen or lymph node biopsy to confirm. In children with hepatosplenomegaly of unknown origin, the possibility of this disease should be considered, regardless of whether it is accompanied by neurological symptoms, with particular attention to those with recurrent pulmonary infections. The initial diagnosis of type A can be made with hepatosplenomegaly, early neurological symptoms and typical foam cells on bone marrow smear, but the diagnosis is still based on enzyme activity testing. Since sphingomyelinase activity is also low in normal leukocytes, cultured skin fibroblasts are usually used as the test material. The enzymatic substrate of choice is 2-hexadecanoylamino-4-nitrophenylphosphorylcholine. The diagnosis can be confirmed by DNA analysis in patients with types A and B. In patients with type C, the ability to lipidate intracellular cholesterol must be tested by a special method.