M4 Triage Protocol to Classify Pregnancies of Unknown Location as Low or High Risk

This triage protocol using hCG levels at presentation and 48 hours later to classify pregnancies of unknown location as high risk, low risk (failed PUL), or low risk (intra-uterine pregnancy). The protocol is based on Condous et al (Ultrasound Obstet Gynecol, 2007) and Van Calster et al (Hum Reprod, 2013), and was further assessed in a single arm interventional trial (Bobdiwala et al, Hum Reprod, 2016). It can be used using this Excel implementation.

How to use it:

• Practical instructions:
  • Open the Excel implementation file.
  • Read and accept the disclaimer.
  • Enter the data of a patient into the blue cells; the message Data complete! then appears below the data.
  • The probabilities of a failed PUL, intra-uterine pregnancy, and ectopic pregnancy are given below the data entry section, and shown in a patient risk bar chart.
  • These risks are turned into a classification
    • if the probability of ectopic pregnancy is at least 5%, the classification is HIGH RISK.
    • Else the classification is LOW RISK (IUP) or LOW RISK (failed PUL) depending on the outcome with highest probability.
  • Contact Ben Van Calster in case of problems (ben.vancalster@med.kuleuven.be)
• Read the important information about the model that is presented in Condous et al (Ultrasound Obstet Gynecol 2007; 29:680-7), Van Calster et al (Hum Reprod 2013; 28:609-616), Bobdiwala et al (Hum Reprod, in press), and in the excel file.