The test characteristics of head circumference measurements for pathology associated with head enlargement: a retrospective cohort study

Table 4 Test Characteristics of Selected HC Percentile Thresholds for Diagnosing Children with IEC, MGCM, or BESS

A	B	C	D	E	G	H	I	K	L	M	N
Threshold	Number in source population	Number diagnosed with IEC, MGCM, or BESS	Number above threshold	Number above threshold with IEC, MGCM, or BESS	Sensitivity E/C	Specificity (B-C-(D-E))/(B-C)	Positive predictive value E/D	Likelihood ratio positive G/(1-H)	Likelihood ratio negative (1-G)/H	Number Needed to Screen B/E	Number Needed to Test D/E
Above CDC 95th	74,428	324	12,325	221	68%	84%	1.8%	4.2	0.4	337	56
Above WHO 95th	74,428	324	18,528	242	75%	75%	1.3%	3.0	0.3	308	77
Above PCN 95th	74,428	324	7,694	193	60%	90%	2.5%	5.9	0.4	386	40
Above CDC 97th	74,428	324	8,373	203	63%	89%	2.4%	5.7	0.4	367	41
Above WHO 97th	74,428	324	13,275	225	69%	82%	1.7%	3.9	0.4	331	59
Above PCN 97th	74,428	324	4,532	167	52%	94%	3.7%	8.8	0.5	446	27
Above CDC 99.6th	74,428	324	2,030	129	40%	97%	6.4%	15.5	0.6	577	16
Above WHO 99.6th	74,428	324	3,438	155	48%	96%	4.5%	10.8	0.5	480	22
Above PCN 99.6th	74,428	324	711	69	21%	99%	9.7%	24.6	0.8	1,079	10
Crossed 2 IMPL-CDC	64,015	321	29,206	223	69%	54%	0.8%	1.5	0.6	287	131
Crossed 2 IMPL-WHO	64,015	321	22,462	162	50%	65%	0.7%	1.4	0.8	395	139
Crossed 2 IMPL-PCN	64,015	321	13,831	156	49%	79%	1.1%	2.3	0.7	410	89
Crossed 4 IMPL-CDC	64,015	321	5,727	103	32%	91%	1.8%	3.6	0.7	622	56
Crossed 4 IMPL-WHO	64,015	321	4,372	66	21%	93%	1.5%	3.0	0.9	970	66
Crossed 4 IMPL-PCN	64,015	321	1,703	55	17%	97%	3.3%	6.7	0.8	1,143	30
Crossed 6 IMPL-CDC	64,015	321	490	17	5%	99%	3.5%	7.1	1.0	3,766	29
Crossed 6 IMPL-WHO	64,015	321	556	17	5%	99%	3.1%	6.3	1.0	3,766	33
Crossed 6 IMPL-PCN	64,015	321	130	10	3%	> 99%	7.7%	16.5	1.0	6,402	13

IEC (intracranial expansive condition); MGCM (metabolic or genetic condition associated with macrocephaly); BESS (benign enlargement of the subarachnoid spaces); CDC (Centers for Disease Control head circumference growth curves); WHO (World Health Organization head circumference growth curves); PCN (primary care network head circumference growth curves); IMPL (increasing multiple percentile lines). The negative predictive value (C-(D-E))/(C-D) was 99.9% for all thresholds.

ISSN: 1471-2431