When should TORCH (Toxoplasmosis, Other, Rubella, Cytomegalovirus, Herpes) infections be tested for in pregnant women?

TORCH Testing in Pregnant Women: Evidence-Based Recommendations

Primary Recommendation

Routine universal TORCH screening is not recommended for all pregnant women in the United States; instead, testing should be targeted based on specific clinical indications, risk factors, or concerning ultrasound findings. 1, 2

Standard Screening Approach by TORCH Component

Syphilis (The "O" in TORCH)

• All pregnant women must be screened with serologic testing at the first prenatal visit 1
• High-risk women require repeat testing in the third trimester (28 weeks) and again at delivery 1
• Universal delivery screening is mandated in many states; no infant should be discharged without maternal syphilis status documented at least once during pregnancy 1
• Any woman delivering a stillborn infant after 20 weeks must be tested 1

Hepatitis B (Part of "Other")

• All pregnant women must be screened for HBsAg at the first prenatal visit 1
• Repeat testing late in pregnancy for HBsAg-negative women at high risk (injection drug users, women with concurrent STDs) 1

HIV (Part of "Other")

• HIV testing should be offered to all pregnant women at the first prenatal visit 1

Toxoplasmosis

• Routine universal screening is NOT recommended for low-risk pregnant women 1, 2
• Targeted screening should be offered when:
  • Ultrasound findings suggest TORCH infection (intracranial calcification, microcephaly, hydrocephalus, ascites, hepatosplenomegaly, severe IUGR) 2
  • Maternal symptoms suggest acute infection 1
  • Patient has known risk factors for T. gondii exposure 2
  • Maternal clinical signs: thrombocytopenia (7.1% infection rate) or elevated liver enzymes (3.0% infection rate) 3

Rubella

• No routine prenatal screening is specified in current U.S. guidelines, though immunity status is typically assessed as part of standard prenatal care 1

Cytomegalovirus (CMV)

• Routine universal screening is NOT recommended 1
• Consider testing when:
  • Ultrasound findings suggest congenital infection 2
  • Maternal symptoms suggest primary infection 1
  • HIV-infected women with CD4+ counts <100/mm³ (high risk for CMV disease reactivation) 4
  • Maternal clinical signs: thrombocytopenia or elevated liver enzymes 3

Herpes Simplex Virus (HSV)

• Routine prenatal serologic screening is NOT recommended 1, 4
• Routine serial cultures are NOT indicated for women with history of recurrent genital herpes in the absence of third-trimester lesions 1
• Cultures at delivery may guide neonatal management for women with recurrent herpes history 1

Critical Testing Principles

When TORCH Testing is Indicated

Maternal-related indications (higher yield): 3

• Fever with thrombocytopenia (7.1% infection rate)
• Elevated liver enzymes (3.0% infection rate)
• Gastroenteritis with systemic symptoms
• Clinical suspicion of acute infection

Fetal-related indications (lower yield but important): 2, 3

• Intracranial calcification
• Microcephaly
• Hydrocephalus
• Ascites
• Hepatosplenomegaly
• Severe intrauterine growth restriction
• Polyhydramnios or oligohydramnios

Laboratory Confirmation Requirements

All positive results from commercial laboratories must be confirmed at reference laboratories before intervention, particularly for toxoplasmosis where approximately 60% of positive IgM results are false positives 1, 5

For suspected acute toxoplasmosis: 1, 2

• Send samples directly to toxoplasmosis reference laboratory to avoid delays
• Repeat testing within 2-3 weeks
• Consider starting spiramycin immediately without waiting for confirmatory results
• IgG avidity testing helps determine timing of infection

Special Populations

HIV-Infected Pregnant Women

• Test for T. gondii IgG antibodies at initial HIV diagnosis; if positive, obtain IgM to rule out acute infection 4
• Screen for CMV if CD4+ count <100/mm³ due to reactivation risk 4
• Syphilis screening at first visit with repeat testing in third trimester if at continued risk 4
• HSV serologic testing has no routine value 4

Immunocompromised Women

• Screening for toxoplasmosis is recommended due to reactivation risk and potential for toxoplasmosis encephalitis 2

Common Pitfalls to Avoid

• Screening only symptomatic or high-risk women for toxoplasmosis will miss up to 50% of infected pregnant women at risk of transmission 1
• Misinterpreting positive IgG alone as active infection rather than past exposure 5
• Failing to confirm positive results from non-reference laboratories, especially for toxoplasmosis IgM 1, 5
• Testing for toxoplasmosis via amniocentesis before 18 weeks gestation or less than 4 weeks after suspected maternal infection leads to false-negative results 2
• Ordering routine serial HSV cultures in asymptomatic women with recurrent herpes history 1

Clinical Context

The evidence demonstrates that maternal-indicated TORCH testing (based on clinical symptoms) has significantly higher yield than fetal-indicated testing (based on ultrasound findings alone), detecting 10.8% of neonates with confirmed TORCH infection versus lower rates with fetal indications 3. However, both approaches remain important as they identify different at-risk populations.