The importance of initial screening of mildly elevated abnormal serum aminotransferase levels without repeat testing
Cobbold and colleagues suggested that repeat testing of mildly raised
serum aminotransferases is warranted prior to screening for liver disease.
However, there are several important considerations related to Hepatitis
disease progression, demographics, and cost effectiveness that warrant
initial screening without repeat testing.
The American Gastroenterology Association (2002), Canadian Medical
Association (2005), and the Center for Disease Control (2006) all released
guidelines to screen patients with mild elevations of liver enzymes for
Hepatitis B(HBV) and Hepatitis C(HCV) without repeat testing.1 In
Hepatitis B and C, the liver function tests commonly fluctuate
intermittently from normal to abnormal and do not correlate well with
liver histology.2 At least 16% of patients with chronic Hepatitis C
infection and 13% of patients with nonalcoholic fatty liver disease have
varying degrees of histological damage despite showing persistently normal
aminotransferase levels.3,4 Thus, repeating an abnormal liver function
test and having a normal value on repeat testing does not ensure that the
initial value was erroneous, but rather proves that there is biochemical
variability. 1 Both HBV and HCV rapidly produce and viral loads can become
quite significant before any elevations of ALT/AST are observed. The
various manifestations of both diseases can also be seen with high viral
loads in the absence of transaminase elevations. Additionally, as viral
loads increase, there is an increased risk of viral mutations, increased
incidence of extraintestinal manifestations, increased incidence of
hepatocellular carcinoma, secondary treatment resistance, and an increased
risk for progression of disease.
Lastly, it is cost effective to initially screen for Hepatitis B and
C in areas with high prevalence of disease or high risk populations.5 We
therefore suggest that initial screening, without repeat testing be highly
considered in the aforementioned context.
References:
1. AGA Technical Review on the Evaluation of Liver Chemistry Tests,
GASTROENTEROLOGY 2002;123:1367-1384
2. Haber MM, West AB, Haber AD, Reuben A. Relationship of
aminotransferases to liver histological status in chronic hepatitis C. Am
J Gastroenterol 1995;90:1250 1257.
3. Gholson CF, Morgan K, Catinis G, Favrot D, Taylor B, Gonzalez E, et
al.Chronic hepatitis C with normal aminotransferase levels: a clinical
histological study. Am J Gastroenterol 1997;92(10):1788-92.
4 Mofrad P, Contos MJ, Haque M, Sargeant C, Fisher RA, Luketic VA, et
al.Clinical and histologic spectrum of nonalcoholic fatty liver disease
associated with normal ALT values. Hepatology 2003;37(6):1286-92.
5 Sroczynski G., Esteban E., et. all. Long-term effectiveness and cost-
effectiveness of screening for Hepatitis C virus infection.
Competing interests:
No competing interests
08 November 2010
Viplove Senadhi
PGY-3 (Final Year) in Internal Medicine and Journal Reviewer
Rapid Response:
The importance of initial screening of mildly elevated abnormal serum aminotransferase levels without repeat testing
Cobbold and colleagues suggested that repeat testing of mildly raised
serum aminotransferases is warranted prior to screening for liver disease.
However, there are several important considerations related to Hepatitis
disease progression, demographics, and cost effectiveness that warrant
initial screening without repeat testing.
The American Gastroenterology Association (2002), Canadian Medical
Association (2005), and the Center for Disease Control (2006) all released
guidelines to screen patients with mild elevations of liver enzymes for
Hepatitis B(HBV) and Hepatitis C(HCV) without repeat testing.1 In
Hepatitis B and C, the liver function tests commonly fluctuate
intermittently from normal to abnormal and do not correlate well with
liver histology.2 At least 16% of patients with chronic Hepatitis C
infection and 13% of patients with nonalcoholic fatty liver disease have
varying degrees of histological damage despite showing persistently normal
aminotransferase levels.3,4 Thus, repeating an abnormal liver function
test and having a normal value on repeat testing does not ensure that the
initial value was erroneous, but rather proves that there is biochemical
variability. 1 Both HBV and HCV rapidly produce and viral loads can become
quite significant before any elevations of ALT/AST are observed. The
various manifestations of both diseases can also be seen with high viral
loads in the absence of transaminase elevations. Additionally, as viral
loads increase, there is an increased risk of viral mutations, increased
incidence of extraintestinal manifestations, increased incidence of
hepatocellular carcinoma, secondary treatment resistance, and an increased
risk for progression of disease.
Lastly, it is cost effective to initially screen for Hepatitis B and
C in areas with high prevalence of disease or high risk populations.5 We
therefore suggest that initial screening, without repeat testing be highly
considered in the aforementioned context.
References:
1. AGA Technical Review on the Evaluation of Liver Chemistry Tests,
GASTROENTEROLOGY 2002;123:1367-1384
2. Haber MM, West AB, Haber AD, Reuben A. Relationship of
aminotransferases to liver histological status in chronic hepatitis C. Am
J Gastroenterol 1995;90:1250 1257.
3. Gholson CF, Morgan K, Catinis G, Favrot D, Taylor B, Gonzalez E, et
al.Chronic hepatitis C with normal aminotransferase levels: a clinical
histological study. Am J Gastroenterol 1997;92(10):1788-92.
4 Mofrad P, Contos MJ, Haque M, Sargeant C, Fisher RA, Luketic VA, et
al.Clinical and histologic spectrum of nonalcoholic fatty liver disease
associated with normal ALT values. Hepatology 2003;37(6):1286-92.
5 Sroczynski G., Esteban E., et. all. Long-term effectiveness and cost-
effectiveness of screening for Hepatitis C virus infection.
Competing interests: No competing interests