Better in their words…

On September 17, 2025, in an apparent effort to defend former CDC official Dr. Susan Monarez from not being able to answer difficult questions posed by Senator Rand Paul, CNN’s chief medical correspondent Dr. Sanjay Gupta claimed that hepatitis B screening during pregnancy has a 10% false negative rate.

Let me be blunt: That is false, and it matters—both scientifically and politically.

The Claim and Its Context

According to viewers and transcripts of the CNN segment, Dr. Gupta stated (paraphrased here):

There is a risk of babies getting hepatitis B from their mothers because the prenatal screen has about a 10% false negative rate.

Let’s pause. This isn’t a subtle distinction or a footnote. This is a statement about diagnostic accuracy—the core engine of clinical medicine and public health protocols.

If true, it would imply that 1 in 10 pregnant women with hepatitis B are missed during screening. That would suggest catastrophic system failure—improper reassurance, unprotected infants, unadministered HBIG, and a hidden epidemic of chronic perinatal infection. But that is not what the evidence shows.

The Medical Reality in the US

Standard Prenatal Screening Uses High-Sensitivity Immunoassays

Prenatal screening for hepatitis B surface antigen (HBsAg) is mandated in the United States. All pregnant women are tested, typically during the first prenatal visit, using laboratory-based serologic assays (not point-of-care rapid tests).

According to the U.S. Preventive Services Task Force (USPSTF) in its 2019 evidence-based recommendation:

“The sensitivity and specificity of immunoassays for detecting HBsAg are greater than 98%.”
(JAMA, 2019. PMID: 31334800)

In other words, the false negative rate of the actual screening test used in obstetric care is less than 2%, not 10%.

CDC and ACOG Agree: It’s a High-Performance Test

CDC guidance and the American College of Obstetricians and Gynecologists (ACOG) both recommend universal HBsAg screening with high-accuracy lab methods. Nowhere do they suggest that 1 in 10 infected women go undetected due to test failure.

Even in high-risk populations, such as mothers from endemic countries or those with HIV co-infection, the test’s performance holds. The main risks lie not in test sensitivity, but in:

• Interval infections during pregnancy
• Programmatic errors (missed testing, late prenatal care)
• Rare viral escape mutants, detectable with next-gen assays

Where the 10% Figure Actually Comes From

To give Dr. Gupta the benefit of the doubt, it’s possible—though not evident—that he was referencing global rapid diagnostic tests (RDTs), used in low-resource settings. A 2017 meta-analysis in BMC Infectious Diseases found that some RDTs for HBsAg had:

• Pooled sensitivity ~90%
• False negative rate ~10%

But those RDTs are not used for prenatal screening in the United States. They are for field screening, humanitarian contexts, or emergency triage. They are not part of our perinatal protocol, and the 10% is irrelevant for the discussion on HepB vaccination on the day of birth.

Referencing that figure—without qualification—on national television misrepresents both the quality of U.S. care and the true risks to infants.

Why This Misinformation Is Dangerous

When a prominent physician tells millions of viewers that a crucial pregnancy screening test is only 90% effective, a cascade of confusion and fear follows:

• Pregnant women question their test results.
• Providers face second-guessing from patients.
• Policymakers are fed distorted data that could alter public health policy.
• And worst of all, it implies that our system fails 1 in 10 babies, which is empirically false.

This also undermines legitimate critiques of the hepatitis B birth dose. Some have questioned the ethics of universal vaccination at birth, especially when the mother has tested negative during pregnancy. But if people believe those tests miss 10% of infections, the rationale for universal birth dosing seems more solid—even if it’s built on fiction.

That’s narrative laundering, not science.

What’s Really at Stake: Evidence-Based Policy

First, Gupta could have used the CNN platform to educate on treatments available (see comparison study).

If Dr. Gupta, Dr. Monarez, or any CDC-aligned spokesperson wants to defend hepatitis B policy—including universal infant vaccination—they must do so using actual data, not exaggerated test failure rates.

The real numbers are:

• 85–90% transmission risk for HBsAg⁺/HBeAg⁺ mothers if they are untreated
• ~30% for HBsAg⁺/HBeAg⁻
• <1% residual risk with proper HBIG and vaccine timing
• <2% false negative rate for standard HBsAg screening

This is why both CDC and WHO recommend maternal antiviral therapy(tenofovir) when viral load exceeds 200,000 IU/mL—not because the screen fails, but because viral load is a better predictor of breakthrough transmission.

We don’t need to make up flaws in the test. We need to improve adherence to guidelines, ensure postpartum follow-up, and focus on the handful of high-risk cases—not pretend our lab tests are coin flips.

Final Word

The role of a medical correspondent—especially one with Gupta’s reach—is not to shield bureaucrats or rescue narratives. It’s to inform the public accurately, especially when the issue is clinical, consequential, and measurable.

So let’s set the record straight:

No, Dr. Gupta, the hepatitis B prenatal screening test does not have a 10% false negative rate.
The science is stronger than that. Let’s treat it with the respect it deserves.

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CITATIONS

Primary Evidence on Test Accuracy

U.S. Preventive Services Task Force (USPSTF), 2019. Screening for Hepatitis B Virus Infection in Pregnant Women: US Preventive Services Task Force Reaffirmation Recommendation Statement. JAMA. 2019 Jul 23;322(4):349-354. https://jamanetwork.com/journals/jama/fullarticle/2739705PMID: 31334800

Kemper et al., 2019. Screening for Hepatitis B Virus Infection in Pregnant Women: Evidence Report and Systematic Review for the US Preventive Services Task Force. JAMA. 2019 Jul 23;322(4):360-367. https://jamanetwork.com/journals/jama/fullarticle/273970 PMID: 31334780

Misused Source for the “10%” Figure (Not Applicable to U.S. Screening)

BMC Infectious Diseases, 2017. Rapid diagnostic tests for the detection of recent hepatitis B virus infections: a meta-analysis. https://bmcinfectdis.biomedcentral.com/articles/10.1186/s12879-017-2772-3DOI: 10.1186/s12879-017-2772-3

Perinatal Transmission Risk and Postexposure Prophylaxis

CDC Pink Book: Epidemiology and Prevention of Vaccine-Preventable Diseases (14th Edition), Hepatitis B Chapter. https://www.cdc.gov/vaccines/pubs/pinkbook/hepb.html (See “Perinatal HBV Infection” and “Maternal Management” sections.)

CDC MMWR 2018 – “Notes from the Field: False-Negative Hepatitis B Surface Antigen Test Results in a Hemodialysis Patient — Nebraska, 2017” https://www.cdc.gov/mmwr/volumes/67/wr/mm6710a6.htm DOI: 10.15585/mmwr.mm6710a6

CDC MMWR 2023 – “Testing and Clinical Management of Pregnant Persons with Hepatitis B Virus Infection” https://www.cdc.gov/mmwr/volumes/72/wr/mm7215a1.htm DOI: 10.15585/mmwr.mm7215a1

HBeAg-Negative Mutations and Reactivation Risk. EASL Clinical Practice Guidelines: Management of Chronic Hepatitis B Virus Infection. J Hepatol. 2017;67(2):370–398. https://www.journal-of-hepatology.eu/article/S0168-8278(17)30185-X/fulltext

Tseng TC, et al. 2012. Serum hepatitis B surface antigen levels help predict spontaneous HBsAg seroclearance in patients with low HBV DNA levels. Gastroenterology. 2012 Apr;142(4):720–729.e9. https://www.gastrojournal.org/article/S0016-5085(12)00185-3/fulltext DOI: 10.1053/j.gastro.2012.02.007

Tacke F, et al. 2004. Precore and basal core promoter mutations in HBV genome and their role in HBeAg-negative hepatitis B. J Virol. 2004 Aug;78(16):8524–8535. https://journals.asm.org/doi/10.1128/JVI.78.16.8524-8535.2004 DOI: 10.1128/JVI.78.16.8524-8535.2004