Tumor Lysis Syndrome (TLS): is caused by massive release of potassium, phosphate and nucleic acids into the body. The result is high-levels of crystal formation which can cause extensive end organ damage, especially the kidneys. TLS is defined by lab criteria and is considered an oncologic emergency. Patients most at risk are those which have received chemotherapy, radiation therapy or glucocorticoid therapies within the last 24-48 hours and patients with aggressive lymphomas.

Associated symptoms: Patients with TLS reflect the following symptoms due to the metabolic abnormalities: lethargy, nausea & vomiting, diarrhea, anorexia, hematuria, cardiac dysrhythmias (or worsening of CHF), muscle cramps, seizures and possibly sudden death

Clinical criteria: The Cairo Bishop Classification System is the most widely accepted medical guideline to define this diagnosis and assign the level of severity. The following metabolic changes are used when they occur within 3-7 days after the administration of chemotherapy.


Cairo Bishop Classification: (Requires 2 criteria for validation)



OR, change from baseline:

Uric acid

≥ 8 mg/dL

25% increase from documented baseline


≥ 6 mEq/L

25% increase from documented baseline


≥ 6.5 mg/dL (child) or

≥ 4.5 mg/dl adult

25% increase from documented baseline


≤ 7 mg/dL

25% decrease from documented baseline

Treatment: The measures taken to treat TLS include: aggressive hydration, IV sodium bicarb, strict I&O, daily electrolyte monitoring, administration of hypouricemic agents such as allopurinol, or Febuxostat, and at times renal dialysis.  Often these patients require transfer to the ICU for monitoring of cardiac and renal function.

This diagnosis is often a target for audit review since it is an MCC and not a common complication of antineoplastic therapy. Denials of this diagnosis are often based on lack of physician documentation linking the symptoms and resultant lab abnormalities on TLS, especially in those patients with chronic conditions. An example would be new onset, or reoccurrence, of a cardiac arrhythmia without any link of a possible, or probable cause from TLS.  Additionally, when lab criteria are borderline, denials of this diagnosis argue TLS did not occur and the preventative measures taken were effective. Therefore, physician documentation linking the symptoms, clinical criteria and treatment is very important.

By Barb Brant, MPA, RN, CDIP, CCDS, CCS