Testing of Antenatal Samples

At December 2010, an antenatal testing service was provided by the National Health Service Blood and Transplant (NHSBT) Birmingham centre for samples sent via Cambridge, Liverpool, Oxford and Sheffield. NHSBT performs this service under contract with local trusts, for women undergoing routine antenatal testing for hepatitis B, HIV and syphilis infections and rubella susceptibility. Details of the number of samples tested and the number positive are reported by NHSBT testing laboratories each month. In addition, the age and ethnicity of all women who are found positive for any marker is requested. If an antenatal sample is found positive for hepatitis B, syphilis or HIV, (or negative for rubella), the local health service should undertake confirmatory testing and refer for appropriate care and follow-up as necessary.

Table 1: Antenatal samples tested by NHSBT for HBsAg, HIV, syphilis (anti-T. pallidum) and rubella: January to December 2010

	HBsAg¹	HIV¹	Syphilis¹	Rubella¹
Number positive (negative for rubella)	416	182	165	2280
Number tested	121,048	110,746	124,363	61,176
Percent positive (negative for rubella)	0.34	0.16	0.13	3.73
Number HBsAg/HBeAg positive (percent)²	57 (14.3)	–	–	–

1. There were a number of samples with markers of dual or triple infection: HBV/HIV 6, HBV/syphilis 6, HIV/syphilis 4, HBV/HIV/syphilis 1, and a number of samples with markers for infection combined with rubella susceptibility: HBV/rubella 12, HIV/rubella 5 and syphilis/rubella 5.

2. 18/416 samples were not tested for anti-HBe/HBeAg where status known from previous results.

Table 2: Characteristics of women with positive (negative for rubella) antenatal samples tested by NHSBT: January to December 2010

Characteristics where known¹	HBsAg²		HIV²		Syphilis²		Rubella²
Mean age of women with positive samples (negative for rubella)	29 years		31 years		29 years		23 years
Ethnic group	Number positive	*Percent positive*	Number positive	*Percent positive*	Number positive	*Percent positive*	Number negative	Percent negative
Asian	63	*0.67*	3	*0.03*	13	*0.14*	354	3.96
Black	62	*2.81*	62	*2.98*	12	*0.54*	91	4.55
Caribbean Black	1	*0.17*	5	*0.88*	4	*0.68*	13	2.26
Caucasian	26	*0.06*	5	*0.01*	34	*0.08*	1258	3.62
Chinese	38	*12.20*	0	0	1	*0.32*	17	7.10
Mixed/Other	28	*1.34*	3	*0.16*	6	*0.28*	69	*3.79*

1.Denominator ethnicity data was provided by NHSBT Red Cell Immunohaematology. The proportions for each ethnic group was applied to the centre data. Ethnicity was reported for approximately half of women with HBsAg, HIV and syphilis positive samples and 80% of women with samples negative for rubella. Age was not known for 9 HBsAg, 3 HIV, and 2 syphilis positive women and 2 women negative for rubella.
2. There were a number of women with samples with markers of dual infection: HBV/HIV 6, HBV/syphilis 6, HIV/syphilis 4, HBV/HIV/syphilis 1, and a number women with samples with markers for infection combined with rubella susceptibility: HBV/rubella 12, HIV/rubella 5, and syphilis/rubella 5.
See the Health Protection Report for further details and cumulative data.

Note that after an internal review it was decided that NHSBT would work with hospitals to transfer routine antenatal microbiological screening services out of NHSBT by end of 2010-11. See the Hospitals and Science website communications February 2008 NBS Antenatal Letter. An antenatal toolkit has information for users and potiential service providers.

For more information on NHSBT surveillance of testing among antenatal women, please contact Claire Reynolds.
For more information on national surveillance of testing among antenatal women please see the Pregnant Women page and the NHS Infectious Diseases in Pregnancy Screening programme (IDPS) Programme.

Last reviewed: 25 March 2011