What Human Chorionic Gonadotropin (hCG) level confirms a positive pregnancy test?

From the Guidelines

A patient is considered pregnant when the serum hCG value is greater than 5 mIU/mL. This threshold is based on the most recent and highest quality study available, which was published in 2024 in the journal Radiology 1. According to this study, values of 5 mIU/mL or less may occur in healthy nonpregnant patients, but a value greater than 5 mIU/mL is generally considered indicative of pregnancy. Some key points to consider when interpreting hCG levels include:

• The multitude of hCG assays available, which may have varying specific values and terminology 1
• The importance of referring to local laboratory guidelines, as some laboratories may not use the modifier beta 1
• The possibility of elevated hCG levels unrelated to pregnancy, such as with pituitary dysfunction or neoplasia 1 It is also worth noting that hCG levels typically double every 48-72 hours in early pregnancy, reaching approximately 100 mIU/mL by the time of a missed period. However, the exact threshold for confirming pregnancy is the key consideration, and a serum hCG value greater than 5 mIU/mL is the established threshold 1.

From the Research

HCG Levels for Confirming Pregnancy

To confirm a positive pregnancy, the following HCG levels are considered:

• A quantitative serum hCG level of ≥5 mIU/mL is defined as the criterion standard for a positive pregnancy test 2
• A study found that using a 5 UI/l hCG positivity threshold, the sensitivity and specificity of a point-of-care hCG whole-blood test were 89.7% and 100%, respectively 3
• Another study used a 10 UI/l hCG positivity threshold and found that the sensitivity and specificity of the same test were 96.3% and 100%, respectively 3

Factors Affecting HCG Test Results

The following factors can affect HCG test results:

• The type of HCG test used, with qualitative tests being less analytically sensitive than quantitative tests 4
• The timing of the test, with HCG levels varying throughout pregnancy 4
• The presence of certain medical conditions or substances that can interfere with HCG test results 4

Comparison of HCG Testing Methods

Different studies have compared the effectiveness of various HCG testing methods, including:

• Ultrasound versus HCG testing for verifying the effectiveness of medical abortion, with HCG testing found to be more reliable 5
• Point-of-care versus laboratory-based HCG testing, with point-of-care tests found to be rapid and accurate 2, 3