Performance Characteristics Detection Limit:  2 mIU/mL; Linear Range:  2-20,0000 mIU/mL; Linear correlation coefficient R ≥ 0.990; Precision: within batch C.V. is ≤ 15%; between batches C.V. is ≤ 20%; Accuracy: the relative deviation of the measurement results shall not exceed ± 15% when the accuracy calibrator prepared by β-hCG national standard or standardized accuracy calibrator are tested. Cross-Reactivity:The following substances do not interfere with the β-hCG test results at the indicated concentrations: LH at 200 mIU/mL, TSH at  200 mIU/L and FSH at  200 mIU/L 1. Store the detector buffer at 2～30℃. The buffer is stable up to 18 months. 2. Store Aehealth Ferritin Rapid Quantitative test cassette at 2～30℃, shelf life is up to 18 months. 3. Test cassette should be used within 1 hour after opening the pack. Human chorionic gonadotropin (hCG) is a glycoprotein with a molecular weight of 38000, secreted by the placenta. Like other glycoprotein hormones (hLH, hTSH and hFSH), hCG contains two different subunits, an α- and a β-chain, linked by noncovalently bindings. The primary structures of the α subunits of these hormones are virtually identical, while their β subunits, responsible for the immunological and biological specificity, are different. Thus a specific determination of hCG can only be made by the determination of its β component. The measured hCG content results almost exclusively from intact hCG molecules but there can be a contribution, albeit a usually negligible fraction of the total, from the free β-hCG subunit.  hCG appears in the serum of pregnant women five days after the implantation of blastocyst and its concentration continually increases until the third month of the pregnancy. The maximum concentration can reach values up to 100 mIU/ml. Then the hormone level drops to 25 mIU/ml and stays around this value until the last trimester.