hcv: diagnostic testing and...
TRANSCRIPT
David E. Bernstein, MD, FACG
HCV: Diagnostic Testing and Staging
HCV: Diagnostic Tests
Necessary Not Necessary• HCV Antibody• HCV-RNA• Genotype
• ALT• IL28 B
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David E. Bernstein, MD, FACG
ALT as a Sole Trigger for Screening Misses Some Infected Patients
Patients* With Hepatitis C Infection
15%PersistentlyElevated ALT
42%PersistentlyNormal ALT
43%IntermittentlyElevated ALT
Elevated ALT
*4 serum ALT level measurements during 25 months of follow-up (n = 1042). These results are from a prospective community-based study that evaluated liver enzyme levels in patients with hepatitis C who had a history of prior drug use.
ALT = alanine aminotransferase.
Inglesby TV, et al. Hepatology. 1999;29:590-596.
Hepatitis C Antibody Testing
• 2 types of tests– Standard-goes to lab– Point of Care Testing
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David E. Bernstein, MD, FACG
Detection of Anti-HCV IgG:Rapid Tests
• Do not require complicated instrumentation/testing by skilled staff• Potentially generate results within an hour (potential point-of-care use)• CDC evaluation of 3 rapid tests (Orasure, Chembio,and Medmira)
– Assays based on recombinant antigens derived from core, NS3, NS4, and NS5 proteins in an immunochromatographic format
– Specificity: >99%; sensitivity: 86% to 99%• OraQuick HCV Rapid Antibody Test (CLIA-waived)
– FDA approved with fingerstick, whole-blood, and venous blood specimens from individuals aged >15 years and at risk for HCV infection or persons with signs and symptoms of hepatitis
– Not approved for general screening• Typically more expensive versus conventional immunoassays• Not designed for testing large batches of specimens• Results available in ~20 minutes
Kamili S, et al. Clin Infect Dis. 2012;55(suppl 1):S43-S48.
Steps for Fingerstick or Venipuncture Specimen Collection
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David E. Bernstein, MD, FACG
Detection of Anti-HCV IgG:Immunoassays
• Diagnostic specificity– >99% for 3rd generation assays
F l ti lt
Signal-to-Cutoff Ratios(FDA-Approved, Screening Assays)
(Detect Anti-HCV IgG)• False-negative results– Undergoing hemodialysis– Immunocompromised patients
• Signal-to-cutoff ratios – Predict a true antibody positive results
>95% of the time, regardless of the anti-HCV prevalence or characteristics of the population tested
(Detect Anti HCV IgG)
Ratio
Enzyme immunoassay (manual)Ortho HCV Version 3.0Abbott HCV EIA 3.0
>3.8>3.8
Chemiluminescence immunoassay (automated)
Vitros anti-HCVAdvia Centaur HCV
>8.0>11.0
Kamili S, et al. Clin Infect Dis. 2012;55(suppl 1):S43-S48.
Microparticle immunoassay (automated)
Architect anti-HCV >10.0
Chemiluminescence microparticle immunoassay (automated)
Architect anti-HCV >5.0
HCV Antibody
• Does not diagnose disease• Positive antibody may mean:
– Active disease– Previous infection now cleared– False positive
• All positive antibodies requires confirmatory• All positive antibodies requires confirmatory HCV-RNA testing
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David E. Bernstein, MD, FACG
Detection of Virus-Specific Molecules:HCV RNA and Genotype
• Nucleic acid testing for HCV RNA remains the gold standard
PCR b h d DNA i l
HCV RNA AssaysLLD/– PCR, branched DNA signal
amplification, and transcription-mediated amplification
– Specificity: up 99% across all genotypes 1-6
– Essential for monitoring response to therapy
Method (IU/mL)
QualitativeAmplicor HCV v2.0 (Roche)COBAS Amplicor HCV 2.0 (Roche)Ampliscreen (Roche)Versant HCV RNA (Gen-Probe)UltraQual HCV (National Genetics)Procleix HIV-1/HCV (Gen-Probe)
RT-PCR (manual)RT-PCR (semi-auto)RT-PCR (semi-auto)
TMA (manual)RT-PCR
TMA (manual)
5050
<501010
<50
QuantitativeAmplicor HCV Monitor (Roche)COBAS Amplicor HCV Monitor
(Roche)Versant HCV RNA 3.0 (Gen-Probe)
RT-PCR (manual)RT-PCR (semi-auto)
bDNA (semi-auto)
5050
615
Kamili S, et al. Clin Infect Dis. 2012;55(suppl 1):S43-S48.
( )COBAS Ampliprep/TaqMan
(Roche)Real Time HCV/m2000sp/m2000rt
(Abbott)HCV SuperQuant
(National Genetics)LCx HCV RNA-Quantitatie (Abbott)
( )qPCR (semi-auto)
qPCR (semi-auto)
RT-PCR (semi-auto)
RT-PCR (maual)
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General Clinical Statements on HCV Viral Load
• Amount of virus not clinically significant10 000 000 IU/ l b ild di i h i• 10,000,000 IU/ml may be mild disease or cirrhosis
• 50,000 IU/l may be mild disease or cirrhosis• Viral load not predictive of disease progression• Viral load predictive of maternal-fetal transmission• Viral load critical for assessing adherence to therapyg py
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David E. Bernstein, MD, FACG
Hepatitis C Genotype
• Important in determining which therapy to use
• Important in determining duration of therapy• Sub-typing important• Common US genotypes
1 1b 2 3 4– 1a, 1b, 2 ,3 ,4– Less common 5 and 6
Recommended Laboratory Testsfor Chronic HCV Infection
Test Purpose
Hepatitis C antibody by Screening for past or presentHepatitis C antibody byenzyme immunoassay (EIA)
Screening for past or present HCV infection
PCR for HCV RNA Confirmation of positive EIAGenotype Determines therapy and
duration
AASLD and IDSA.Available at: http://www.hcvguidelines.org/full-report-view. Version January 29, 2014.
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David E. Bernstein, MD, FACG
HCV Diagnostic Assays:What the Results Mean
Anti-HCV
HCV RNA Interpretationp
+ + Acute or chronic HCV depending on the clinical context
+ False positive HCV antibodyResolved infectionLow-level intermittent viremia
+ Early acute HCV infectionChronic HCV in setting of immunosuppressed stateFalse positive HCV RNA test
Absence of HCV infection
AASLD and IDSA.Available at: http://www.hcvguidelines.org/full-report-view. Version January 29, 2014.
Pre-Treatment Assessment
• HgB• Cr• Liver enzymes• HCV-RNA• Genotype• Assessment of disease severity
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David E. Bernstein, MD, FACG
Options for Liver Fibrosis Assessment:Degree of Fibrosis = Disease severity
Liver Biopsy FibroScanSerum Biomarkers
Serum Biomarkers assessing Fibrosis in Chronic HCV
– Fibrotest– Fibrosis Score 4
– HepascoreL k I d– Fibrosis Score 4
– AST to platelet ratio (APRI)
– FibroSpect II– Enhanced liver fibrosis
score (ELF)
– Lok Index– Virahep– Fibroindex– AST to ALT ratio– Platelet count
– Fibrosis probability index
Castera L. Gastroenterology. 2012;142:1293-1302.
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David E. Bernstein, MD, FACG
Serum FibroTest: A Continuous Variable (n=1,270)
Expected FibroTest
0.20
0.40
0.60
0.80
1.00
Fib
roTe
st F3-F40.73-0.74
F30.59-0.72
F20.49-0.58
F1-F20.32-0.48
F40.75-1.00
FibrosisFibroTest
Poynard, Clin Chem 2004; 50:1344-55.
0.000 1 2 3 4
Fibrosis StageF00.00-0.21
F0-F10.22-0.27
F10.28-0.31
Serum biomarkers
• Excellent at predicting minimal fibrosis• Excellent at predicting cirrhosis• May need 2-3 tests• Unclear if cost effective
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David E. Bernstein, MD, FACG
Liver Biopsy for assessing fibrosis
• “Gold standard”• Sampling error (< 1/50,000th of the liver)
– Cirrhosis missed in up to 20%– Grade of inflammation and stage of fibrosis
under-scored in shorter and narrower specimens
Adequate specimen:q p≥ 1.5 cm long (≥ 2 cm preferable; ≥ 2.5 cm best)
≥ 1.0 mm wide (≥ 1.4 mm preferable)≥ 6 portal triads (≥ 11 is better) RegevRegev A, et al. Am J A, et al. Am J GastroenterolGastroenterol 2002; 97:26142002; 97:2614--8.8.
Crawford AR, et al. Crawford AR, et al. HepatologyHepatology 1998; 28:3231998; 28:323--31.31.ColloredoColloredo G, et al. J G, et al. J HepatolHepatol 2003; 39:2392003; 39:239--44.44.
DemetrisDemetris AJ, AJ, RuppertRuppert K. J K. J HepatolHepatol 2003; 39:2752003; 39:275--7.7.BedossaBedossa P, et al. P, et al. HepatologyHepatology 2003; 38:14492003; 38:1449--57.57.
Malik AH, et al. Aliment Malik AH, et al. Aliment PharmacolPharmacol TherTher 2004; 19:5452004; 19:545--9.9.
Fibrosis Area: 65%
Sampling Error of Liver Biopsy
Fibrosis Area: 15%Courtesy of M. Pinzani, Florence
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David E. Bernstein, MD, FACG
Liver Biopsy: Potential Complications
• PainBl di• Bleeding
• Bile Peritonitis• Puncture of gallbladder, colon, kidney• Pneumothorax, hemothorax, pleural effusion• Arteriovenous fistulaArteriovenous fistula• Sepsis• Needle track seeding with tumor
Bravo AA, et al. N Bravo AA, et al. N EnglEngl J Med 2001; 344:495J Med 2001; 344:495--500.500.PiccininoPiccinino F, et al. J F, et al. J HepatolHepatol 1986; 2:1651986; 2:165--73.73.
McGill DB, et al. Gastroenterology 1990; 99:1396McGill DB, et al. Gastroenterology 1990; 99:1396--400.400.
Bleed following Liver Biopsy
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David E. Bernstein, MD, FACG
Summary : Liver Biopsy
• Gold standard• Poor patient acceptance• Safe with potential complications• Limited availability
Fibrosis = Stiffness• A key parameter of soft biological tissues
– Often related to a pathological state– Palpation widely used in routine clinical practice– Palpation widely used in routine clinical practice
10 9
10 10Bone
Stiff
ness
(Pa)
10 2
10 3
10 4
10 5
10 6
10 7
10 8 Cartilage
Contracted musclePalpable nodulesCirrhotic liverNormal breast tissues Relaxed muscleNormal liver
“When the liver is stiff, prognosis is bad”
Aphorisms, Hippocrate (460-370 BC)
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David E. Bernstein, MD, FACG
Transient Elastography measures stiffness
• Fibroscan®• MRI elastography
Fibroscan
•Examination time < 5 minutes•Median value of 10 successful acquisitions•Fasting 2-4 hours•Performed on expiration
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David E. Bernstein, MD, FACG
The FibroScan ProbeThe FibroScan Probe
Ultrasound(Shear wave speed measurement)
Actuator(Shear wave generator)
Skin
2.5 cm6.5 cm
Measurement PositionMeasurement Position
4 cm
1 cm 4 cm3
Explored Tissue
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David E. Bernstein, MD, FACG
Shear Wave PropagationShear Wave Propagation Map Map
Depth
TimeSpeed = Distance / Time
Summary Data DisplaySummary Data DisplayMedian shear wave speed, stiffness & IQR data
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David E. Bernstein, MD, FACG
FIBROSCAN
Transient elastography: What the Clinician needs to know
• What is the underlying disease• Other evidence of advanced liver disease• Factors that can affect the test
– Is the patient fasting?– BMI
B d f i fl ti (ALT l l)– Burden of inflammation (ALT level)– ETOH use– Cholestasis
Tapper et al. Clin Gastro Hep 2015;13:27-36
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David E. Bernstein, MD, FACG
kPa CutoffsDisease Cirrhosis Comments
Hepatitis C 12.5 kPa 7.3 kPa suggests significant fibrosis
Hepatitis B 11.7 kPa If normal ALT, consider treating at 9.0 kPa
NAFLD 10.3 kPa Consider performing CAP* (controlled attenuation parameter) assessment
ETOH 22.7 kPa if drinking12.5 kPa if abstinent
Biliary liver disease 17.9 kPa Must know alkaline phosphatase
Portal HTN 20 kPa suggests HVPG > 1050.7 kPa suggests high risk of varicealbleeding
* Assessed in decibels per meter, currently proprietary algorithm
Confounders of VCTE
Know the ALT
Confounders
Inflammation
Non-fasting
Ch l t i
Inexperience
Congestion
Fast 3-4 hours
Cholestasis
Alcohol Obesity
Know the alk phos
Use XL probe for BMI > 30Determine drinkingstatus
Examine for Right heartfailure
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David E. Bernstein, MD, FACG
Magnetic resonance elastography for detecting hepatic fibrosis Magnetic resonance elastography uses a vibrating device to induce shear waves in internal organs, which are
detected by a modified magnetic resonance imaging machine.
CAREY E , and CAREY W D Cleveland Clinic Journal of Medicine 2010;77:519-527
©2010 by Cleveland Clinic
Importance of Determining Degree of Fibrosis
• Determines prognosis• With new therapies, timing may be before,
during or after therapy– If possible, do not delay therapy
• May determine eligibility for treatment with anti-viral therapyanti-viral therapy
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David E. Bernstein, MD, FACG
Recommendations for when and in whom to initiate treatment
• Treatment is recommended for patients with chronic HCV pinfection.
• Rating: Class I, Level A• Treatment is assigned the highest priority for those
patients with advanced fibrosis (Metavir F3), those with compensated cirrhosis (Metavir F4), liver transplant recipients, and patients with severe extrahepatic hepatitis C
• Based on available resources, treatment should be prioritized as necessary so that patients at high risk for liver-related complications and severe extrahepatichepatitis C complications are given high priority
Accessed 1/20/2015:http://www.hcvguidelines.org/full-report/when-and-whom-initiate-hcv-therapy
Diagnosis and Staging Combined for Efficiency
• Initial Visit (PCP)HCV A tib d
• Second visit (Specialist)R i HCV RNA– HCV Antibody
• POCT
– Send off • HCV-RNA• Genotype
– Review HCV-RNA– Review genotype– Obtain Fibroscan®– Initiate anti-viral therapy
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