1st-order laboratory parameters-obligatory laboratory tests.
- Complete blood count [leukocytosis (increase in white blood cell count) with risk of leukostasis syndrome at levels >100,000/μl; displacement of normal hematopoiesis (blood formation)]. Caution. The leukocyte count is little evidence of leukemia, because acute leukemias can also be subleukemic, i.e., accompanied by normal or even slightly increased leukocyte count.
- Differential blood picture with immunophenotyping [typical is the so-called “hiatus leucaemicus “,i.e. the extensive absence of intermediate maturation stages of myelopoiesis (formation of erythrocytes, granulocytes, monocytes and platelets) in the simultaneous presence of immature blasts and mature leukocytes (segment-nucleated granulocytes)].
- CRP (C-reactive protein)
- Quick, PTT (partial thromboplastin time), fibrinogen, antithrombin 3, D-dimers.
- Urea, creatinine if necessary creatinine clearance.
- Alanine aminotransferase (ALT, GPT), aspartate aminotransferase (AST, GOT), glutamate dehydrogenase (GLDH), LDH.
- Cytology with blood smear, bone marrow aspirate (cytology and histology), if necessary iliac crest punch in a punctio sicca due to a fiber proliferation or in hypocellularity; immunophenotypic classification [proving a blast percentage > 20% in the bone marrow; typical is the so-called “hiatus leucaemicus ” (see above); see also classification according to FAB (French-American-British)].
- Cytogenetic examination and molecular genetics.
- FISH; if cytogenetic analysis is unsuccessful: Detection of translocations such as RUNX1-RUNX1T1, CBFB-MYH11, KMT2A (MLL), and EVI1; or loss of chromosome 5q, 7q, or 17p.
- Molecular genetics (mutations): NPM1, CEBPA, RUNX1, FLT3 (internal tandem duplications (ITD), mutant-wild-type quotient), TKD (codons D853 and I836), TP53, ASXL1.
- Molecular genetics (gene rearrangements): PML-RARA, CBFB-MYH11, RUNX1-RUNX1T1, BCR-ABL1.
* This causes a disturbance of the rheology (flow properties) of the blood due to the extremely high leukocyte count and consequently microcirculatory disorders, which lead to numerous organ damage.
2nd order laboratory parameters – depending on the results of the medical history, physical examination and obligatory laboratory parameters – for differential diagnostic clarification.
- Virus diagnostics: virology and, if necessary, PCR for CMV, EBV, HBV, HCV, HIV.
- Blood group, HLA typing (if allogeneic stem cell transplantation is considered).
- CSF puncture (collection of cerebrospinal fluid by puncture of the spinal canal) for CSF diagnosis – in case of CNS symptoms (to exclude meningeosis leucaemica; in children and adolescents always independent of CNS symptoms).
- Organ, lymph node, and/or skin biopsy (tissue removal from the skin) – if extramedullary manifestation (“outside the bone marrow”) is suspected
- HLA typing (if necessary, also of siblings) + CMV status (in patients suitable for allogeneic stem cell transplantation.
