Table 1.

Referral criteria of three NBS centers in Taiwan

	CFOH borderline/positive	TIP borderline/positive	NTUH borderline/positive
C3 (μM)	6/14	6/12	4.74/8.8 (1st tier)
C3/C2	0.25/0.35	0.25/0.3	0.26
mma (μM)	4.2 (2nd tier)	Pos/Neg	1 (2nd tier)

The first number indicates the cutoff point for resampling, whereas the second number stands for value of immediate referral to confirmatory medical center: NTUH/Taipei Veterans General Hospital. Note in CFOH and in NTUH, a second tier of mma level would be conducted in case of high C3 and/ or C3/C2 value.In TIP, a quantitative test of mma would be performed after detection of elevated C3 or C3/C2