In cell-based HM diagnostics, molecular techniques can specifically detect targeted abnormalities known to have a significant clinical impact; for example qRT-PCR measurement of BCR-ABL1 transcript levels, in chronic myeloid leukemia (CML), allows to detect as few as one malignant cell in 10 × 104 nonmalignant ones [22] and NPM1 quantitative assessment in acute myeloid leukemia (AML) which median sensitivity of detection is 1 × 10−5 [23]. The gene discussed is ABL1; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.