Table 2.

Diagnostic performance of FST and Biosensor as compared with gold-standard spectrophotometry

		Spectrophotometry
		Male		Female
		Deficient	Normal	Deficient	Intermediate	Normal
FST	Deficient	20	0	2	0	0
	Normal	6*	133	2*	22	137
	Total	26	133	4	22	137
Biosensor	Deficient	26	0	4	2†	0
	Intermediate	NA	NA	0	16	9‡
	Normal	0	125	0	4§	121
	Total	26	125	4	22	130

Phenotypes are based on 30% and 70% thresholds for spectrophotometry. For Biosensor, threshold for deficiency is ≤4.8 IU/gHb and 4.9–9.9 IU/gHb for intermediate, both obtained by ROC analysis.

Total sample for Biosensor was 307; total sample for FST was 322 (3 samples were not analysed by FST at the clinic).

Characteristics of discordant samples are reported in online supplemental table 1.

*Enzymatic activities ranging from 12% to 27% of spectrophotometry MM.

†Two Mahidol heterozygotes with activity by spectrophotometry of 33% and 62% of MM.

‡Two Mahidol heterozygotes and seven wild-type samples with enzymatic activity by spectrophotometry ranging from 71% to 113%.

§Three Mahidol heterozygotes and one wild-type samples with enzymatic activity by spectrophotometry ranging from 54% to 64%.

FST, fluorescent spot test; MM, male median; NA, Not applicable; ROC, receiver operating characteristic.