Tumor Lysis Syndrome Workup
For any patient with suspected TLS, immediately obtain a comprehensive laboratory panel including uric acid, potassium, phosphorus, calcium, creatinine, BUN, and LDH, with monitoring frequency of every 6 hours for the first 24 hours in high-risk patients. 1
Essential Laboratory Studies
Core TLS Panel
- Uric acid – critical for diagnosis; laboratory TLS defined by increase >25% from baseline or absolute value ≥8 mg/dL (476 mmol/L) 1
- Potassium – assess for life-threatening hyperkalemia 2
- Phosphorus – elevated due to massive cell lysis 2
- Calcium – typically decreased secondary to hyperphosphatemia 2
- Creatinine and BUN – evaluate renal function and acute kidney injury 1
- Lactate dehydrogenase (LDH) – marker of cell turnover and tissue breakdown 2
Additional Required Studies
- Complete blood count with differential – assess disease burden and cytopenias 2
- Comprehensive metabolic panel – includes sodium and liver function tests 2
- Disseminated intravascular coagulation (DIC) panel – D-dimer, fibrinogen, PT, PTT, particularly important in acute leukemia 2
Monitoring Frequency Based on Risk
High-Risk Patients
Monitor LDH, uric acid, sodium, potassium, creatinine, BUN, phosphorus, and calcium every 12 hours for the first three days, then every 24 hours subsequently. 1 High-risk features include bulky disease (≥10 cm), elevated LDH, high white blood cell count, pre-existing renal impairment, and elevated baseline uric acid. 3
Established TLS
For patients with confirmed TLS, monitor vital parameters and complete laboratory panel every 6 hours for the first 24 hours, then daily thereafter until stable. 1
Imaging Studies
Risk Stratification Imaging
- Chest X-ray – mandatory to rule out mediastinal mass and pleural effusion 2
- CT scan – useful for assessment of TLS risk category before initiating venetoclax in CLL, and for evaluating bulky disease 2
- CT/MRI of head with contrast – only if neurologic symptoms present to detect CNS bleeding or chloromas 2
- Whole-body PET/CT – if lymphoblastic lymphoma suspected 2
Important caveat: Serial CT scans are not recommended for asymptomatic patients. 2
Renal Function Assessment
Use estimated glomerular filtration rate (eGFR) calculated by MDRD formula or Cockroft-Gault equation as reliable surrogates for renal excretion function. 1 Direct measurement of creatinine clearance or eGFR is essential for proper risk stratification and management decisions. 1
Additional Workup Components
Cardiac Assessment
- Echocardiogram or cardiac nuclear medicine scan – required in all patients who will receive anthracyclines, particularly those with prior cardiac history, prior anthracycline exposure, cardiac symptoms, or elderly patients 2
Infection Screening
- Screen for opportunistic infections as clinically appropriate, especially if febrile or symptomatic 2
- Initiate empiric anti-infective therapy when indicated 2
Special Populations
- Pregnancy testing – for all patients of childbearing potential 2
- Testicular examination with scrotal ultrasound – as indicated in male patients, particularly with T-cell ALL where testicular involvement is more common 2
Clinical TLS Definition
Clinical TLS requires laboratory TLS (abnormalities in ≥2 parameters: uric acid, potassium, phosphorus, calcium) PLUS at least one of the following within 7 days: 1, 4
- Renal failure/injury (creatinine >1.5× upper limit of normal)
- Need for renal dialysis
- Cardiac arrhythmia
- Seizure
Critical Pitfalls to Avoid
- Do not delay laboratory monitoring – waiting for symptoms to develop before checking labs can result in life-threatening complications 1
- Do not rely on single time-point measurements – TLS develops rapidly and requires serial monitoring 1
- Do not overlook pre-existing renal impairment – this significantly increases TLS risk and requires more aggressive monitoring 3
- Do not use calcium gluconate for mild hypocalcemia – can precipitate calcium-phosphate crystals in setting of hyperphosphatemia 1