Table 2. Laboratory testing for the differential diagnosis of thrombotic microangiopathy (recommendation grade IA–IB) (5).
| Laboratory | Parameter | Suspected diagnosis |
| Mandatory | ||
| Hematology | Complete differential blood analysis (smear, increased schistocytes fraction) |
Microangiopathic anemia |
| Clinical chemistry | Creatinine, protein excretion in urine LDH, haptoglobin levels |
HUS Hemolysis |
| Coagulation | Quick ↓, PTT ↑, fibrinogen ↓, (D-dimer ↑) | Hyperfibrinolysis, DIC |
| Microbiology/ virology |
Shiga toxin in stool or blood Blood culture Test for HIV, hepatitis B/C |
EHEC-HUS SP-HUS HIV-associated TMA |
| Pregnancy test (for women of childbearing age) |
Beta-HCG | HELLP, eclampsia |
| Immunology | Coombs’ test positive | Autoimmune hemolytic anemia, Evans syndrome |
| ADAMTS13 antigen ↓, ADAMTS13 activity ↓, positive for ADAMTS13 inhibitor |
aTTP | |
| ADAMTS13 antigen ↓, ADAMTS13 activity ↓, negative for ADAMTS13 inhibitor |
cTTP | |
| Special indications | ||
| Immunology | sC5b-9↑, C3↓, C4↓, anti-H-antibody positive | aHUS |
| Bone marrow puncture | Cytology and histology of bone marrow | Bone marrow carcinosis |
| Renal biopsy | Immunohistochemistry | Complement-dependent nephropathy, aHUS |
| Skin biopsy | Immunohistochemistry | TMA |
| Molecular genetics | ADAMTS13 mutation | Congenital TTP (Upshaw–Schulman syndrome) |
| Mutation of factor H, factor I, MCP, C3, DGKE, thrombomodulin, MMACHC, plasminogen | aHUS | |
ADAMTS13: a disintegrin and metalloprotease with thrombospondin type 1 motif, member 13; aHUS: atypical hemolytic uremic syndrome; aTTP: immune-mediated, acquired thrombotic thrombocytopenic purpura; beta-HCG: beta-human chorionic gonadotropin; cTTP: congenital thrombotic thrombocytopenic purpura; DGKE: diacylglycerol kinase E; DIC: disseminated intravascular coagulopathy; EHEC: enterohaemorrhagic Escherichia coli–associated HUS; HELLP: hemolysis, elevated liver enzyme levels, and low platelet levels; HUS: hemolytic uremic syndrome; LDH: lactate dehydrogenase; HIV: human immunodeficiency virus; MCP: membrane cofactor protein; MMACHC: methylmalonate aciduria and homocystinuria type C protein; PTT: partial thromboplastin time; SP-HUS: Streptococcus pneumoniae–induced hemolytic uremic syndrome; TMA: thrombotic microangiopathy