Enter two beta hCG blood draws and the hours between them. We'll calculate the doubling time and compare it to the published Kadar / Barnhart reference ranges.
hCG doubling time alone is not a diagnostic test. Single-point hCG values vary day to day and lab to lab. The reference ranges (Kadar 1981, updated by Barnhart 2004) describe what's typical, not what's required. Some viable pregnancies double slowly; some non-viable pregnancies double normally for a while.
Your provider combines hCG trends with ultrasound, symptoms, and clinical history to interpret. If something looks off, call them — that's exactly what they're there for.
Sources: Kadar et al. 1981 Obstet Gynecol; Barnhart et al. 2004 Obstet Gynecol; Seeber 2012 Fertil Steril.