Summary of investigations to determine the degree of organ involvement and differential diagnosis of an acute TMA
| Investigation . | Tests . | Rationale . |
|---|---|---|
| Hemolytic screen | Hemoglobin, platelet, reticulocytes, LDH, blood film (DCT, haptoglobin) | Diagnosis of MAHAT |
| Renal function | K+, Ur, creatinine urine dipstick: protein/blood/leukocytes protein creatinine ratio | Degree of renal impairment |
| Liver function | Bilirubin | With hemolysis |
| AST/ALT | Question hepatic ischemia | |
| ALP | Liver obstruction | |
| Coagulation screen | PT, APTT, fibrinogen | Normal in TTP/CM-HUS, deranged in DIC |
| Pregnancy test | Urine or serum HCG | In all women of child-bearing age |
| Other biochemistry | Troponin | Degree of cardiac involvement |
| Thyroid function | Useful with pyrexia of TMA to exclude infection | |
| CRP | May be reduced C3 with CM-HUS, C4 in autoimmune disease, eg, SLE | |
| C3/C4 | Consider if possible cancer trigger in men | |
| PSA | ||
| Vitamins | B12/folate | Treat deficiencies, folate may be reduced with haemolysis |
| Virology | Hepatitis A/B/C | Baseline investigations especially pre-PEX |
| HIV +/−viral load | eg, in HSCT | |
| Further virology screen relevant to history, eg, adenovirus, CMV | ||
| Autoimmune screen | ANA/dsDNA | Underlying autoimmune disease |
| RF | ||
| ENA | ||
| ACLA/LA | ||
| Vasculitis screen (if relevant from history) | Anti-GBM antibodies | To exclude Goodpasture’s/underlying vasculitis trigger |
| ANCA | ||
| Microbiology | BCs STEC serology/PCR from stool | With temperature |
| Radiology | USS abdomen | Kidneys’ size, obstruction, lymphadenopathy, organomegaly |
| MRI head | Ischemic changes, infarcts, PRES | |
| CT chest/abdomen/pelvis | If exclude an underlying cancer | |
| Cardiac investigations | ECG echocardiogram | Baseline for cardiac function/conduction defects or ischemia |
| Investigation . | Tests . | Rationale . |
|---|---|---|
| Hemolytic screen | Hemoglobin, platelet, reticulocytes, LDH, blood film (DCT, haptoglobin) | Diagnosis of MAHAT |
| Renal function | K+, Ur, creatinine urine dipstick: protein/blood/leukocytes protein creatinine ratio | Degree of renal impairment |
| Liver function | Bilirubin | With hemolysis |
| AST/ALT | Question hepatic ischemia | |
| ALP | Liver obstruction | |
| Coagulation screen | PT, APTT, fibrinogen | Normal in TTP/CM-HUS, deranged in DIC |
| Pregnancy test | Urine or serum HCG | In all women of child-bearing age |
| Other biochemistry | Troponin | Degree of cardiac involvement |
| Thyroid function | Useful with pyrexia of TMA to exclude infection | |
| CRP | May be reduced C3 with CM-HUS, C4 in autoimmune disease, eg, SLE | |
| C3/C4 | Consider if possible cancer trigger in men | |
| PSA | ||
| Vitamins | B12/folate | Treat deficiencies, folate may be reduced with haemolysis |
| Virology | Hepatitis A/B/C | Baseline investigations especially pre-PEX |
| HIV +/−viral load | eg, in HSCT | |
| Further virology screen relevant to history, eg, adenovirus, CMV | ||
| Autoimmune screen | ANA/dsDNA | Underlying autoimmune disease |
| RF | ||
| ENA | ||
| ACLA/LA | ||
| Vasculitis screen (if relevant from history) | Anti-GBM antibodies | To exclude Goodpasture’s/underlying vasculitis trigger |
| ANCA | ||
| Microbiology | BCs STEC serology/PCR from stool | With temperature |
| Radiology | USS abdomen | Kidneys’ size, obstruction, lymphadenopathy, organomegaly |
| MRI head | Ischemic changes, infarcts, PRES | |
| CT chest/abdomen/pelvis | If exclude an underlying cancer | |
| Cardiac investigations | ECG echocardiogram | Baseline for cardiac function/conduction defects or ischemia |
Samples for ADAMTS13 are taken pre-PEX and for complement mutational analysis, and factor H antibodies will take weeks or months before available.
ALP, alkaline phosphatase; ALT, alanine transaminase; ANA, antinuclear antibody; ANCA, antineutrophil cytoplasmic antibody; anti-GBM, antiglomerular basement membrane; AST, aspartate aminotransferase; BC, blood culture; CMV, cytomegalovirus; CRP, C-reactive protein; CT, computer tomography; DCT, direct coombes test; dsDNA, double-stranded DNA; ECG, electrocardiogram; ENA, extractable nuclear antibody; HCG, human chorionic gonadotropin; K+, potassium; PSA, prostate-specific antigen; RF, rheumatoid antibody; Ur, urea; USS, ultrasound.