Standardization of Hepatitis E Virus (HEV) Nucleic Acid Amplification Technique-Based Assays: an Initial Study To Evaluate a Panel of HEV Strains and Investigate Laboratory Performance

DOI: 10.1128/JCM.02578-10

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Fig. 1.
Phylogenetic analysis of HEV strains evaluated in the study. GenBank accession numbers are shown for reference strains; the numbers of the panel strains are shown in Table 1.
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Fig. 2.
Analysis of viral loads (log₁₀ copies/ml) by laboratory and sample. (a) HRC-HE104 genotype 3a. (b) JRC-HE3 genotype 3b. (c) RKI genotype 3f. (d) HRC-HE15 genotype 4c.

Table 1.

Details of HEV strains evaluated in the study

Genotype	Virus strain	HEV RNA level (copies/ml)^{^a}	GenBank accession no.	Anti-HEV IgM/IgG result^{^b}	ALT level (IU/liter)^{^c}
3a	HRC-HE104	1.6 × 10⁷	AB602891	−/−	36
3b	JRC-HE3	2.5 × 10⁷	AB434146	+/−	398
3f	RKI	1.3 × 10⁶	FJ956757	−/−	Negative
4c	HRC-HE15	1.0 × 10⁶	AB602890	−/−	505

Table 2.

Qualitative analysis of the four HEV strains

↵a For the number of positive test results, a best-case/worst-case percentage is reported for results reported as being simply positive or equivocal.
↵b Data were returned for a total number of 24 tests for each sample. However, in the case of sample 22 (genotype 4c), a false-positive result (as evidenced by the detection of an HEV genotype not represented in the panel) was reported by one laboratory and was not included during the calculation of percent positive results. A breakdown of the original data is shown in Tables S2 to S5 in the supplemental material.

Table 3.

Viral load data for the four HEV strains

Virus strain	Sample	Nominal concn (log₁₀ copies/ml)	No. of samples	Observed viral load (log₁₀ copies/ml)
Virus strain	Sample	Nominal concn (log₁₀ copies/ml)	No. of samples	Geometric mean	SD	95% CI^{^a}	Median	Minimum	Maximum
HRC-HE104	13	6.2	12	5.84	0.64	5.43, 6.24	5.77	4.82	7.48
	11	5.2	12	4.74	0.68	4.31, 5.17	4.72	3.63	6.40
	3	4.2	11	3.85	0.67	3.40, 4.30	3.84	3.11	5.64
	18	3.2	9	3.04	0.66	2.53, 3.54	2.96	2.40	4.49
	17	2.2	6	1.98	0.37	1.59, 2.37	1.94	1.43	2.40
	19	1.2	4	0.10	1.27	−1.93, 2.12	0.00	−1.00	1.38
JRC-HE3	20	6.4	12	6.16	0.72	5.70, 6.61	6.15	4.43	7.70
	23	5.4	12	5.07	1.09	4.38, 5.76	5.14	2.15	7.00
	4	4.4	12	4.21	0.67	3.79, 4.63	4.27	2.60	5.58
	12	3.4	10	3.40	0.60	2.97, 3.83	3.20	2.92	5.00
	10	2.4	6	2.43	1.03	1.35, 3.52	2.36	1.26	4.11
	6	1.4	3	1.40	2.39	−4.53, 7.34	1.43	−1.00	3.78
RKI	1	5.1	12	4.63	0.59	4.26, 5.01	4.57	3.91	6.26
	8	4.1	10	3.77	0.61	3.33, 4.21	3.63	3.20	5.26
	2	3.1	9	2.83	0.69	2.30, 3.37	2.63	1.77	4.28
	16	2.1	6	1.68	1.54	0.06, 3.30	1.80	−1.00	3.28
	21	1.1	3	−0.32	1.18	−3.25, 2.61	−1.00	−1.00	1.04
HRC-HE15	5	5.0	12	4.56	0.69	4.12, 5.00	4.44	3.28	6.28
	14	4.0	10	3.40	0.38	3.13, 3.67	3.44	2.63	4.04
	9	3.0	8	1.83	1.85	0.28, 3.38	2.46	−1.00	4.20
	15	2.0	6	1.02	1.83	−0.90, 2.94	1.35	−1.00	3.85
	22	1.0	3	−1.00	0.00		−1.00	−1.00	−1.00