Corrigendum

Abstract

An error exists in the following article “Detection of trisomy 18 and trisomy 13 using first and second trimester Down’s syndrome screening markers” published in the Journal of Medical Screening Volume 20 Number 2, June 2013, pp.57-65 DOI: 10.1177/0969141313484904,

The errors occur in the modelling of the trisomy 18 and 13 detection rates for the Quadruple, serum Integrated and Integrated tests in this paper. The following should replace the original text:

Abstract (P 57. Results, last sentence): The corresponding detection rates for the Quadruple test were: 5% and 21% (2.00% FPR), 59% and 21% (2.16% FPR) and 59% and 24% (2.28% FPR), and for the Integrated test were: 40% and 60% (2.00% FPR), 92% and 68% (2.12% FPR) and 92% and 74% (2.18% FPR).

Results (Pp 59--60, second paragraph, last sentence): The further addition of a T13 Integrated test has no material effect on the T18 detection rate, but increases the T13 detection rate from 68% to 74% with a small increase in the overall false-positive rate to 2.18%.

Results (Pp 59--60, third paragraph second and third sentences): The addition of a T18 algorithm increases the T18 detection rate from 5% to 59% using the Quadruple test, and from 14% to 87% using the serum Integrated test. There is little advantage in adding a T13 algorithm to the Quadruple test, but there is an increase in the T13 detection rate from 41% to 54% with the addition of a T13 algorithm to the serum Integrated test.

Discussion (Pp 61--62, first paragraph, fourth, fifth and sixth sentences): Similarly, our results showed that 40% of T18 and 60% of T13 pregnancies were detected using the Integrated DS test. Adding the specific T18 algorithm increased these to 92% and 68% respectively, with a small increase in the false-positive rate (to 2.1%). The further addition of the T13 specific algorithm had no material advantage in the detection of T18, but increased the T13 detection rate to 74%.

Discussion (P 62, second paragraph fifth sentence): Only with the Integrated and serum Integrated tests was there a material improvement in the identification of T13 pregnancies with the inclusion of a T13 algorithm (from 60% to 72% for the Integrated test, from 41% to 54% for the Serum Integrated test), but this would mean only about one more T13 pregnancy detected per 100,000 women screened.

Figure 3 (P 60): The following corrects the trisomy 13 detection rates using the Integrated test

Figure 4 (P 61): The following corrects the trisomy 18 and trisomy 13 detection rates using the Quadruple and serum Integrated tests

Table 1 (P 62): The following corrects the trisomy 18 and trisomy 13 detection rates using the Quadruple, serum Integrated and Integrated tests

			Down's syndrome screening test
			Quadruple			Serum Integrated			Integrated
			Additional algorithm(s)
DS test FPR	T18 and T13 FPR's			T18	T18 and T13		T18	T18 and T13		T18	T18 and T13
1%	0.1%	T18 DR	3	47	47	9	82	82	31	88	89
		T13 DR	15	16	18	28	32	45	53	60	68
	0.2%	T18 DR	3	58	58	9	87	88	31	92	92
		T13 DR	15	16	20	28	35	51	53	63	72
	0.3%	T18 DR	3	65	65	9	90	90	31	93	94
		T13 DR	15	16	20	28	37	56	53	65	75
2%	0.1%	T18 DR	5	48	48	14	82	83	40	89	89
		T13 DR	21	21	23	36	39	49	60	65	71
	0.2%	T18 DR	5	59	59	14	87	88	40	92	92
		T13 DR	21	21	24	36	41	54	60	68	74
	0.3%	T18 DR	5	66	66	14	90	90	40	94	94
		T13 DR	21	21	25	36	43	59	60	69	76
3%	0.1%	T18 DR	7	48	48	18	83	83	45	89	89
		T13 DR	25	25	26	41	43	52	64	69	73
	0.2%	T18 DR	7	60	60	18	88	88	45	92	92
		T13 DR	25	25	27	41	45	57	64	70	76
	0.3%	T18 DR	7	66	66	18	90	91	45	94	94
		T13 DR	25	25	28	41	47	61	64	72	78