Table 4.

Summary of seven adults in whom HCV core antigen (HCV-Ag) assay was falsely negative, as compared to PCR for HCV RNA as a gold-standard reference test

Age group (years)	Sex	Patient location	Ethnicity	HIV status	HCV Ag (fmol/L)	HCV Ab (sample/cut-off ratio)	Genotype	HCV viral load (IU/ml)
30–39	F	Sexual health	Unknown	negative	0.0	11.8	N/A	25
40–49	M	Primary care	European	negative	0.0	12.2	N/A	226
50–59	F	Hospital in-patient (General Medicine)	European	positive	0.0	3.1	N/A	302
20–29	M	Prison	European	negative	0.62	14.2	2b	2916
20–29	M	Prison	European	N/A	0.00	12.6	N/A	8232
30–39	F	Hospital out-patient	European	N/A	1.98	15.8	1b	13,860
30–39	M	Prison	European	negative	0.00	12.2	3a	174,834

N/A = not available. Total number of HCV-Ag tests carried out in this period n = 305. None of the patients with a false negative result underwent a repeat Ag test so laboratory error cannot be ruled out in this instance. Threshold for positive HCV-Ag defined as ≥3 fmol/L. Samples are ranked in ascending viral load order