Multicenter evaluation of the first automated Elecsys sFlt-1 and PlGF assays in normal pregnancies and preeclampsia.
OBJECTIVE
Performance evaluation of Elecsys sFlt-1 and PlGF assays.


METHODS
Within-, between-run, total imprecision, functional sensitivity, inter-laboratory comparison, method comparison and lot-to-lot reproducibility were evaluated.


RESULTS
Within- and between-run CVs were below 4% for sFlt-1 >60 and PlGF > 20 pg/mL. Total imprecision CVs were below 4.3%. Functional sensitivity was < 5 pg/mL. Inter-laboratory CVs were <5%. Elecsys correlated well with Quantikine VEGF-R1 (r=0.960) and PlGF (r=0.968). Lot-to-lot comparisons yielded highly correlated results (r>0.999). In healthy pregnancies, the median levels of sFlt-1 remained constant in first (1107 pg/mL) and second trimesters (1437 pg/mL) but increased in the third trimester (2395 pg/mL), while median PlGF levels increased in the first (30 pg/mL) and second trimesters (279 pg/mL) and peaked at 29 to 32 weeks (626 pg/mL) and decreased thereafter (340 pg/mL). The sFlt-1/PlGF ratio is highest in the first trimester (median: 28) but remained constant in the second (median: 4.7) and third trimesters (median: 5.1). In PE/HELPP samples matched for gestational age the sFlt-1 levels were significantly higher (6894-34,624 pg/mL), whereas PlGF levels were lower (9.2-80 pg/mL) and the median sFlt-1/PlGF ratio is much higher (461; range: 121-2614) than in apparently healthy pregnancies (3.6; range: 0.3-105).


CONCLUSIONS
The new Roche Elecsys sFlt-1 and PlGF immunoassay showed excellent precision and reliability. There was a clear difference in the Elecsys sFlt-1/PlGF ratio between samples obtained from women with apparently normal pregnancy at the time of blood collection and those diagnosed with PE/HELLP at the same age of gestation.
Schiettecatte
J
J
UZ Brussels, Brussels, Belgium. Johan.Schiettecatte@uzbrussel.be
Russcher
H
H
Anckaert
E
E
Mees
M
M
Leeser
B
B
Tirelli
A S
AS
Fiedler
G M
GM
Luthe
H
H
Denk
B
B
Smitz
J
J
D000328:Adult; D001331:Automation; D019411:Clinical Laboratory Techniques / Q000592:standards*; D005260:Female; D006801:Humans; D008565:Membrane Proteins / Q000032:analysis*; D015588:Observer Variation; D011225:Pre-Eclampsia / Q000175:diagnosis* / Q000209:etiology; D011247:Pregnancy; D011257:Pregnancy Proteins / Q000032:analysis; D011264:Pregnancy Trimesters; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D040281:Vascular Endothelial Growth Factor Receptor-1 / Q000032:analysis*
D008565:Membrane Proteins; C098069:PIGF protein, human; D011257:Pregnancy Proteins; C501162:FLT1 protein, human; D040281:Vascular Endothelial Growth Factor Receptor-1