Liver Function Tests (LFTs)

In addition to monitoring CBCs and blood differentials, it is critical to monitor liver counts through Liver Function Tests (LFTs) , a group of blood tests that can help to show how well a person's liver is working. LFTs include measurements of total protein , albumin , various liver enzymes such as ALT and AST , alkaline phosphatase (ALP) and bilirubin .

Total Protein measures the amount of proteins in the bloodstream. Normal total protein levels in the bloodstream range from 6.5 to 8.2 gm/dL (grams per deciliter). Two of the main proteins found in the bloodstream are albumin and globulin.

Albumin is a protein made in the liver. If the liver is badly damaged, it can no longer produce albumin. Albumin maintains the amount of blood in the veins and arteries. When albumin levels become very low, fluid can leak out from the blood vessels into nearby tissues, causing swelling in the feet and ankles. Very low levels of albumin may indicate liver damage. The normal albumin range is from 3.9 gm/dL to 5.0 gm/dL.

ALT and AST are enzymes made in the liver. They are also called transaminases . ALT is sometimes called SGPT and AST is sometimes called SGOT . The normal range of ALT levels is between 5 IU/L (International Units per Liter) and 60 IU/L. The normal range of AST levels is between 5 IU/L and 43 IU/L. Elevated liver enzymes may be a sign of hepatotoxicity (liver toxicity).

Alkaline phosphatase (ALP) is another enzyme found in the liver. Abnormally high ALP levels may indicate liver problems. The normal range of ALP is between 30 IU/L and 115 IU/L.

Bilirubin is a yellow fluid produced in the liver. When bilirubin levels are too high, it can cause a condition called jaundice in which the eyes and skin appear yellow, urine becomes very dark and feces are light. There are two measures of bilirubin: Total Bilirubin, which measures the amount of bilirubin in the bloodstream and Direct Bilirubin, which measures the amount of bilirubin made in the liver. Normal total bilirubin levels range from .20 mg/dL (milligrams per decileter) to 1.50 mg/dL. Normal direct bilirubin levels range from .00 mg/dL to .03 mg/dL.

When are abnormal liver function tests (LFTs) cause for concern? Any abnormalities in LFTs should be addressed and monitored closely. Current guidelines suggest stopping IM treatment when transaminases (liver enzymes) are more than five times the upper limit of normal. If liver function begins to return to normal, IM may be resumed at a lower dose, then increased to the prior dose in appropriate cases.

The consumption of alcohol may affect liver function, so it is important to eliminate or moderate one’s alcohol intake while taking IM. Also, acetaminophen (brand name Tylenol) may not be safe to take during treatment with IM since it, also, is metabolized through the liver. One should not take Tylenol or take it only under the guidance of a physician while taking IM.

Reference Ranges for Liver Function Tests

	Reference Range	Units
Total Protein	6.5 – 8.2	gm/dL
Albumin	3.9 – 5.0	gm/dL
ALT	5– 60	IU/L
AST	5 - 43	IU/
Alkaline Phosphase (ALP)	30 – 115	IU/L
Total Bilirubin	.20 – 1.50	mgdL
Direct Bilirubin	.00 – .03	mg/dL

 

How often should liver function tests (LFTs) be performed? Because of concerns regarding hepatotoxity with IM treatment, LFTs should be obtained before IM treatment is started, every other week during the first month of IM treatment, and at least monthly thereafter. Of course, if any indications of liver problems arise, closer monitoring of LFTs is critical.

Low Counts : Many patients (<1% to 46%) experience low blood counts while taking IM due to myelosuppression , the inability of the bone marrow to produce an adequate number of cells. All patients taking IM should have their blood counts monitored closely. Complete blood counts (CBCs) should be monitored weekly in chronic phase patients during the first month of IM treatment. If platelet counts remain over 100,000/mm 3 and absolute neutrophil count (ANC) remains over 1,500/mm 3 , CBC monitoring can be reduced to every two weeks until 12 weeks of IM therapy has been reached. Thereafter, if counts are stable, monitoring may occur monthly or even longer if appropriate. Patients in accelerated or blast crisis should have CBCs performed more often.

Myelosuppression due to IM therapy is more common in patients with CML in the accelerated or blast crisis stages, but can also occur in chronic phase patients. Myelosuppression and low counts are evident by low platelet counts ( thrombocytopenia ), low absolute neutrophil counts ( neutropenia ) and/or low red blood cell counts ( anemia ), usually measured by a decrease in hemoglobin . A mild or moderate reduction in counts may require no intervention at all and the counts often recover with continued therapy. In more extreme cases, depending on the type and severity of the myelosuppresion and the phase of CML, a physician may recommend the use of growth factors such as Neupogen (for neutropenia), Neumega (for thrombocytopenia) and Procrit or Aranesp (for anemia); interruption of treatment with IM; or, in some cases, a transfusion. The article referenced below, “Practical Management of Patients with Chronic Myeloid Leukemia Receiving Imatinib,” discusses these options in further detail.

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