Table 2.

Demographic data and TREC and KREC values for the population tested

Data		Number	%	TREC copies/µl median (IQR)	P-value**	KREC copies/µl median (IQR)	P-value
Gender	male	1144	51.35	83 (52-131)	< 0.05	94 (67-129)	0.63
	female	1076	48.29	91 (56-149)		93.5 (68-138)
	unknown	8	0.36	121 (99-190)	n/a	107 (86-130)	n/a
Ethnicity	Bulgarian	1346	60.41	90 (55-143)	0.806	96 (69-140)	0.48
	Turkish	95	4.26	89 (48-140)		109.5 (83-205)
	Roma	343	15.39	83 (56-143)		94 (72-130)
	Unknown/other	444	19.93	78 (48-128)	n/a	83 (55-121)	n/a
Gestation age	Born at term ≥ 37 week	1955	87.75	88 (55-143)	< 0.05	94 (68-133)	0.97
	Preterm < 37 week	201	9.01	76 (46-119)		95 (62-133)
	Unknown	72	3.23	83 (53-135)	n/a	98 (92-116)	n/a
Weight at birth	LBW ≤ 2500 g	212	9.51	81 (49-127)	< 0.05	84 (58-128)	0.19
	NBW	2012	90.31	87 (54-142)		95 (68-134)
	Unknown	4	0.18	103 (83-118)	n/a	78 (72-85)	n/a
Overall samples		2228	100	87 (54-140)	n/a	94 (68-133)	n/a

^**the Kruskal-Wallis test and the Mann-Whitney U test were used for comparison between groups (p-values were calculated at significance level 5%); IQR – interquartile range; n/a – not applicable; LBW – low birth weight; NBW – normal birth weight