Tests
1st tests to order
serum uric acid
Test
Biochemistry should be performed prior to initiation of cancer treatment, and for 2 to 3 days after initiation of treatment.
Elevated uric acid prior to initiation of cancer treatment correlates with large tumor burden and is considered an independent risk factor for TLS.[2][9][29]
If there is evidence of TLS, treatment should be initiated and biochemistry repeated at least twice daily until normalized.
Result
≥476 micromol/L (≥8 mg/dL) or 25% increase from baseline
serum phosphate
Test
Biochemistry should be performed prior to initiation of cancer treatment, and for 2 to 3 days after initiation of treatment.
Elevated phosphate prior to initiation of cancer treatment is an independent risk factor for TLS.[2][30]
If there is evidence of TLS, treatment should be initiated and biochemistry repeated at least twice daily until normalized.
Result
children: ≥2.1 mmol/L (≥6.5 mg/dL) or 25% increase from baseline; adults ≥1.45 mmol/L (≥4.5 mg/dL) or 25% increase from baseline
serum potassium
Test
Biochemistry should be performed prior to initiation of cancer treatment, and for 2 to 3 days after initiation of treatment.
Hyperkalemia is a defining feature of laboratory TLS.[2]
If there is evidence of TLS, treatment should be initiated and biochemistry repeated at least twice daily until normalized.
Result
≥6.0 mmol/L (≥6.0 mEq/L) or 25% increase from baseline
serum calcium
Test
Biochemistry should be performed prior to initiation of cancer treatment, and for 2 to 3 days after initiation of treatment.
Hypocalcemia is a defining feature of laboratory TLS.[2]
If there is evidence of TLS, treatment should be initiated and biochemistry repeated at least twice daily until normalized.
Result
≤1.75 mmol/L (≤7 mg/dL) or 25% decrease from baseline
CBC
Test
CBC should be performed prior to initiation of cancer treatment, and for 2 to 3 days after initiation of treatment.
Leukocytosis prior to initiation of cancer treatment correlates with large tumor burden and is considered an independent risk factor for TLS.[9][29]
Result
elevated WBC levels (>25,000/microliter) increase risk of TLS
serum lactate dehydrogenase (LDH)
Test
Biochemistry should be performed prior to initiation of cancer treatment, and for 2 to 3 days after initiation of treatment.
Elevated LDH prior to initiation of cancer treatment correlates with large tumor burden and is considered an independent risk factor for TLS.[9][29][30]
If there is evidence of TLS, treatment should be initiated and biochemistry repeated at least twice daily until normalized.
Result
elevated
serum creatinine
Test
Biochemistry should be performed prior to initiation of cancer treatment, and for 2 to 3 days after initiation of treatment.
Elevated creatinine prior to initiation of cancer treatment is an independent risk factor for TLS.[2][30]
Pre-existing renal impairment (elevated serum creatinine ≥1.5 times the upper limit of normal), dehydration (with elevated blood urea nitrogen), and volume depletion are predisposing risk factors for TLS that may be modifiable and should be identified prior to initiation of cancer treatment.[1][28]
If there is evidence of TLS, treatment should be initiated and biochemistry repeated at least twice daily until normalized.
Result
≥1.5 times the upper limit of normal
serum blood urea nitrogen (BUN)
Test
Biochemistry should be performed prior to initiation of cancer treatment, and for 2 to 3 days after initiation of treatment.
Increased BUN may be observed.[46]
Pre-existing renal impairment (elevated serum creatinine ≥1.5 times the upper limit of normal), dehydration (with elevated BUN), and volume depletion are predisposing risk factors for TLS that may be modifiable and should be identified prior to initiation of cancer treatment.[1][28]
If there is evidence of TLS, treatment should be initiated and biochemistry repeated at least twice daily until normalized.
Result
elevated with renal impairment, acute kidney injury, or dehydration
urine pH
Test
Should be checked prior to initiation of cancer treatment and always in the presence of hyperuricemia.
Uric acid is poorly soluble in water and becomes less soluble in an acidic environment (urine pH <5).[14] Uric acid crystals can precipitate in renal tubules and cause tubular obstruction and nephropathy.
Result
pH ≤5
Tests to consider
ECG
Test
In the presence of hyperkalemia, hyperphosphatemia, and hypocalcemia, an ECG with or without continuous cardiac monitoring is required as life-threatening arrhythmias may develop.
Continuous cardiac monitoring is advised during any pharmacologic treatment of an arrhythmia or when potassium is significantly high (>7 mmol/L [>7 mEq/L]).
Abnormalities with hyperkalemia include peaked T waves, prolongation of PR and QRS intervals and flattening of P waves. This might be followed by atrioventricular conduction blocks and ventricular fibrillation or asystole. In hypocalcemia, QT prolongation may be seen, which predisposes to ventricular arrhythmias.
Result
arrhythmia
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