Original Paper Vox Sang 1992;62:98-101
C. K . Lin R. Chu K. B. Li S. Leong Blood Transfusion Service, Hong Kong Red Cross, Kowloon, Hong Kong
A Study of Hepatitis C Virus Antibodies and Serum Alanine Amino Transferase in Blood Donors in Hong Kong Chinese
................................................................................................. Abstract The reference range of serum alanine amino transferase (ALT) for the local population was established by testing 5,000 random voluntary Chinese blood donors of various age groups of both sexes. In addition, 1,769 serum samples with elevated ALT levels were also collected for anti-HCV assays using both the Abbott and Ortho anti-hepatitis C virus (HCV) assay kits. The relationship between serum ALT and anti-HCV tests was studied and the performances of both kits used were compared. It was found that while the prevalence of serum anti-HCV was 0.4% among hepatitis B surface antigen-negative donors with normal ALT, subjects with ALT between 2 and 3 standard deviations (SD) and >3 SD above the mean level had respective prevalence of anti-HCV3 and 9.5 times that of the normal ALTsubjects. Both anti-HCV kits were found to identify in majority the same positive population among the different groups of subjects studied. In addition, it was observed that for subjects who were anti-HCV-positive, the higher the serum ALT level, the higher the mean anti-HCV ELISA ratio and this observation was similar for both anti-HCV kits used. We conclude that: (1) there is a direct relationship between serum ALTlevel and anti-HCV positivity by E I A ; (2) there is a direct correlation between serum ALT level and anti-HCV ELISA ratio, and (3) both Abbott and Ortho anti-HCV kits perform similarly in the identification of positive serum samples.
.....................
Introduction
Non-A non-B hepatitis (NANBH) has been the major cause of transfusion-associated hepatitis after the implementation of routine hepatitis B surface antigen (HBsAg) screening of donated blood [l]. It was demonstrated that
Received: January 2Y. I Y Y I Revised manuscript received: May 21. I Y Y I Accepted: June 12. l Y Y l
blood donors who were associated with an NANBH case in recipients often had elevated levels of alanine amino transferase (ALT) o r were positive for antibody to the core antigen of hepatitis B virus (anti-HBc); hence, by excluding donors who had either markers, one third of transfusion-associated NANBH might be prevented
Dr. Che Kit Lin. Assistant Director Blood Transfusion Service. Hong Kong Red Cros\ 15. King's Park Rise. Kowloon Hong Kong
1992 5. Karger AG. Bnsel (XH2-YI WJ7/Y2/06??-(XW)8 $2.75/0
'i1
[la]. Both ALT and anti-HBc tests were widely adopted as surrogate markers to reduce the incidence of transfusion-associated NANBH, though they were both considered nonspecific. ALT test was also incorporated in the routine screening of donated blood in Hong- Kong- while anti-HBc was not because of a high local prevalence (33.5%) [personal data]. The development of a recombinant based immunoassay for detection of specific hepatitis C virus antibodies (anti-HCV) by the Chiron Corporation had led to assay studies of serum samples from posttransfusion NANBH patients and implicated donors, and acute and chronic NANBH patients in USA, Italy and Japan, which showed results indicating that HCV was the major etiological agent of NANBH [ 5 , 61. We had studied the relationship between ALT and anti-HCV using such assays and discussed the value of routine ALT and antiHCV tests. In addition, the performance of the two commercially available kits, i.e. Abbott and Ortho anti-HCV assay kits were compared.
Materials and Methods All serum samples were collected from voluntary Chinese blood donors at the blood donation centers in Hong Kong during routine blood collection from January to August, 1990. All samples were tested for ALT and HBsAg in addition to other routine tests. All HBsAg-positive samples were excluded from this study. The study was carried out in a blinded fashion with no specific consent from individual donors. ALT were measured by an automated enzyme kineticsystem using the Cobas Fara. a centrifugal analyzer and ALAT Unikit (Roche diagnostica). The reference range of serum ALT for the local population was established by testing 5,000 random voluntary Chinese blood donorsof various age groups. Serum collected was then classified into three groups according to the serum ALT level: group I: ALT = normal (male 4 3 U/1; female 3 SD (male >88 U/I; female >47 UA), 2,522 group I, 956 group I1 and 813 group I11 serum samples were thus obtained for this study. Anti-HCV assay was performed using an ELISA system (Ortho diagnosticsystems, Raritan, N. J. and Abbott laboratories, Chicago, North Ill.). A surface-coated recombinant HCV C-100-3 antigen (Chiron Corporation) was incubated with diluted serum samples according to the procedures as instructed by the manufacturers. Samples were considered reactive when the absorbance of reaction mixtures was above the cutoffvalue. Reactive samples were then assayed again in duplicate and considered positive if at least 2 o f 3test determinations were reactive. Anti-HCV ELISA ratios were obtained by optical density (OD) of sampledcutoff value. Serum HBsAg was performed by enzyme-linked immunoassay (Abbott laboratories, Chicago, North Ill.). The X'test with Yatescorrection and Pearson's correlation coefficient test were used for statistical analysis.
Tablel. Range of serum ALT level of Chinese blood donors in HongKong Male ALT, UA
Female ALT, UA
2SD 3SD
7-53 4-88
5-30 348
Geometric mean
19
12
Table 2. Results of anti-HCV EIA in different groups of subjects according to serum ALTlevel Subjects
Total tested
2,522 956
Group I Group I1 Group I11
813
Anti-HCV positive n
%
11 11 31
0.4 1.2 3.8
X' = 57.5 with Yates correction. p < 10".
Results
~~~~l~~ of the Serum ALT reference range determination for the local population are shown in table 1. It was found that the normal reference range for males, 7-53 u/1 (mean 19) was appreciably higher - than that for females, 5-30 U/1 (mean 12). Resuits of anti-HCV E I A are shown in table 2. Eleven blood donors of group I subjects were positive with the anti-HCV EIA assay, giving a prevalence of 0.4% (11/2,522) among healthy HBsAg-negative blood donors of normal ALT. Group I1 and I11 subjects were found to have anti-HC' prevalence of 1.2 (11/956) and 3.8% (31/813), which was 3 and 9.5 times that of group 1. Obviously, the prevalence of HCV infection was significantly higher in donors with elevated Serum ALT level (pC10"). A comparison of performance of the two anti-HCV test kits used in this study is shown in table 3. Both kits identified in majority the Same positive populations, though the Ortho kit picked UP slightly more Positive cases among group11 subjects. The result of the assay obtained by both kits was statistically significant with a correlation coefficient of 0.67 (p
C. K . Lin R. Chu K. B. Li S. Leong Blood Transfusion Service, Hong Kong Red Cross, Kowloon, Hong Kong
A Study of Hepatitis C Virus Antibodies and Serum Alanine Amino Transferase in Blood Donors in Hong Kong Chinese
................................................................................................. Abstract The reference range of serum alanine amino transferase (ALT) for the local population was established by testing 5,000 random voluntary Chinese blood donors of various age groups of both sexes. In addition, 1,769 serum samples with elevated ALT levels were also collected for anti-HCV assays using both the Abbott and Ortho anti-hepatitis C virus (HCV) assay kits. The relationship between serum ALT and anti-HCV tests was studied and the performances of both kits used were compared. It was found that while the prevalence of serum anti-HCV was 0.4% among hepatitis B surface antigen-negative donors with normal ALT, subjects with ALT between 2 and 3 standard deviations (SD) and >3 SD above the mean level had respective prevalence of anti-HCV3 and 9.5 times that of the normal ALTsubjects. Both anti-HCV kits were found to identify in majority the same positive population among the different groups of subjects studied. In addition, it was observed that for subjects who were anti-HCV-positive, the higher the serum ALT level, the higher the mean anti-HCV ELISA ratio and this observation was similar for both anti-HCV kits used. We conclude that: (1) there is a direct relationship between serum ALTlevel and anti-HCV positivity by E I A ; (2) there is a direct correlation between serum ALT level and anti-HCV ELISA ratio, and (3) both Abbott and Ortho anti-HCV kits perform similarly in the identification of positive serum samples.
.....................
Introduction
Non-A non-B hepatitis (NANBH) has been the major cause of transfusion-associated hepatitis after the implementation of routine hepatitis B surface antigen (HBsAg) screening of donated blood [l]. It was demonstrated that
Received: January 2Y. I Y Y I Revised manuscript received: May 21. I Y Y I Accepted: June 12. l Y Y l
blood donors who were associated with an NANBH case in recipients often had elevated levels of alanine amino transferase (ALT) o r were positive for antibody to the core antigen of hepatitis B virus (anti-HBc); hence, by excluding donors who had either markers, one third of transfusion-associated NANBH might be prevented
Dr. Che Kit Lin. Assistant Director Blood Transfusion Service. Hong Kong Red Cros\ 15. King's Park Rise. Kowloon Hong Kong
1992 5. Karger AG. Bnsel (XH2-YI WJ7/Y2/06??-(XW)8 $2.75/0
'i1
[la]. Both ALT and anti-HBc tests were widely adopted as surrogate markers to reduce the incidence of transfusion-associated NANBH, though they were both considered nonspecific. ALT test was also incorporated in the routine screening of donated blood in Hong- Kong- while anti-HBc was not because of a high local prevalence (33.5%) [personal data]. The development of a recombinant based immunoassay for detection of specific hepatitis C virus antibodies (anti-HCV) by the Chiron Corporation had led to assay studies of serum samples from posttransfusion NANBH patients and implicated donors, and acute and chronic NANBH patients in USA, Italy and Japan, which showed results indicating that HCV was the major etiological agent of NANBH [ 5 , 61. We had studied the relationship between ALT and anti-HCV using such assays and discussed the value of routine ALT and antiHCV tests. In addition, the performance of the two commercially available kits, i.e. Abbott and Ortho anti-HCV assay kits were compared.
Materials and Methods All serum samples were collected from voluntary Chinese blood donors at the blood donation centers in Hong Kong during routine blood collection from January to August, 1990. All samples were tested for ALT and HBsAg in addition to other routine tests. All HBsAg-positive samples were excluded from this study. The study was carried out in a blinded fashion with no specific consent from individual donors. ALT were measured by an automated enzyme kineticsystem using the Cobas Fara. a centrifugal analyzer and ALAT Unikit (Roche diagnostica). The reference range of serum ALT for the local population was established by testing 5,000 random voluntary Chinese blood donorsof various age groups. Serum collected was then classified into three groups according to the serum ALT level: group I: ALT = normal (male 4 3 U/1; female 3 SD (male >88 U/I; female >47 UA), 2,522 group I, 956 group I1 and 813 group I11 serum samples were thus obtained for this study. Anti-HCV assay was performed using an ELISA system (Ortho diagnosticsystems, Raritan, N. J. and Abbott laboratories, Chicago, North Ill.). A surface-coated recombinant HCV C-100-3 antigen (Chiron Corporation) was incubated with diluted serum samples according to the procedures as instructed by the manufacturers. Samples were considered reactive when the absorbance of reaction mixtures was above the cutoffvalue. Reactive samples were then assayed again in duplicate and considered positive if at least 2 o f 3test determinations were reactive. Anti-HCV ELISA ratios were obtained by optical density (OD) of sampledcutoff value. Serum HBsAg was performed by enzyme-linked immunoassay (Abbott laboratories, Chicago, North Ill.). The X'test with Yatescorrection and Pearson's correlation coefficient test were used for statistical analysis.
Tablel. Range of serum ALT level of Chinese blood donors in HongKong Male ALT, UA
Female ALT, UA
2SD 3SD
7-53 4-88
5-30 348
Geometric mean
19
12
Table 2. Results of anti-HCV EIA in different groups of subjects according to serum ALTlevel Subjects
Total tested
2,522 956
Group I Group I1 Group I11
813
Anti-HCV positive n
%
11 11 31
0.4 1.2 3.8
X' = 57.5 with Yates correction. p < 10".
Results
~~~~l~~ of the Serum ALT reference range determination for the local population are shown in table 1. It was found that the normal reference range for males, 7-53 u/1 (mean 19) was appreciably higher - than that for females, 5-30 U/1 (mean 12). Resuits of anti-HCV E I A are shown in table 2. Eleven blood donors of group I subjects were positive with the anti-HCV EIA assay, giving a prevalence of 0.4% (11/2,522) among healthy HBsAg-negative blood donors of normal ALT. Group I1 and I11 subjects were found to have anti-HC' prevalence of 1.2 (11/956) and 3.8% (31/813), which was 3 and 9.5 times that of group 1. Obviously, the prevalence of HCV infection was significantly higher in donors with elevated Serum ALT level (pC10"). A comparison of performance of the two anti-HCV test kits used in this study is shown in table 3. Both kits identified in majority the Same positive populations, though the Ortho kit picked UP slightly more Positive cases among group11 subjects. The result of the assay obtained by both kits was statistically significant with a correlation coefficient of 0.67 (p
