What is the role of the TORCH (Toxoplasma, Rubella, Cytomegalovirus, Herpes Simplex Virus) test in pregnancy for a woman of childbearing age with a history of exposure to or infection with TORCH pathogens?

TORCH Testing in Pregnancy

Direct 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

---

Screening Strategy by Individual TORCH Component

The "TORCH panel" as a blanket test is not evidence-based. Each component requires a distinct approach:

Syphilis (Treponema pallidum) - UNIVERSAL SCREENING REQUIRED

• All pregnant women must be screened with serologic testing (RPR or VDRL) at the first prenatal visit. 2, 1
• High-risk women require repeat testing in the third trimester (28 weeks) and again at delivery. 2, 1
• Many states mandate universal screening at delivery; no infant should be discharged without documented maternal syphilis status at least once during pregnancy. 2, 1

Hepatitis B - UNIVERSAL SCREENING REQUIRED

• All pregnant women must be screened for HBsAg at the first prenatal visit. 2, 1

HIV - UNIVERSAL SCREENING RECOMMENDED

• HIV testing should be offered to all pregnant women at the first prenatal visit with appropriate counseling and informed consent. 2, 1

Toxoplasmosis - TARGETED SCREENING ONLY

• Routine universal screening for toxoplasmosis is NOT recommended for low-risk pregnant women in the United States. 2, 1, 3
• Targeted screening should be offered when: 2, 1, 3
  • Maternal symptoms suggest acute infection (lymphadenopathy, flu-like illness)
  • Ultrasound findings suggest congenital infection (intracranial calcification, microcephaly, hydrocephalus, ascites, hepatosplenomegaly, severe IUGR)
  • Patient has known risk factors (exposure to undercooked meat, cat feces, soil contamination)
• Screening only symptomatic or high-risk women will miss up to 50% of infected pregnant women at risk of transmission. 2, 1

Rubella - UNIVERSAL SCREENING RECOMMENDED

• Rubella immunity status should be documented at the first prenatal visit. 4
• High seroprevalence (87%) exists due to vaccination programs. 5

Cytomegalovirus (CMV) - NO ROUTINE SCREENING

• Routine universal CMV screening is not recommended. 2, 4
• Consider testing when ultrasound findings suggest congenital infection. 4, 3

Herpes Simplex Virus (HSV) - NO ROUTINE SCREENING

• Routine serial cultures for HSV are not indicated for women with a history of recurrent genital herpes in the absence of lesions during the third trimester. 2
• Cultures at delivery may guide neonatal management. 2
• Prophylactic cesarean section is not indicated without active genital lesions at delivery. 2

---

Critical Testing Principles to Avoid Misdiagnosis

Confirmation at Reference Laboratories is MANDATORY

• All positive results from commercial, hospital-based, or clinic-based laboratories MUST be confirmed at reference laboratories before intervention, particularly for toxoplasmosis. 2, 1, 3
• Approximately 60% of positive Toxoplasma IgM results from non-reference laboratories are false positives when retested at reference laboratories. 1, 4
• Reference laboratories provide clinical interpretation of serologic results and estimation of timing of acute maternal infection. 2

Timing of Testing Matters

• For suspected acute toxoplasmosis, samples should be sent immediately to reference laboratories to avoid delays in diagnosis and treatment initiation. 2
• Repeat testing should be performed within 2-3 weeks if acute infection is suspected. 3

---

When to Suspect and Test for TORCH Infections

Ultrasound Findings Requiring TORCH Evaluation

Screen for toxoplasmosis and CMV when ultrasound demonstrates: 3

• Intracranial calcification
• Microcephaly
• Hydrocephalus
• Ascites
• Hepatosplenomegaly
• Severe intrauterine growth restriction

Maternal Risk Factors for Toxoplasmosis

• Exposure to undercooked meat or cat feces 2
• However, only 48% of mothers of infants with congenital toxoplasmosis had clinical symptoms or reported risk factors. 2

---

Common Pitfalls and How to Avoid Them

Pitfall #1: Ordering Blanket "TORCH Panels"

• The TORCH acronym is outdated and leads to unnecessary testing. 1
• Order specific tests based on clinical indication, not reflexive panels. 1

Pitfall #2: Failing to Confirm Positive Results

• Never act on positive IgM results from commercial laboratories without reference laboratory confirmation. 2, 1, 3
• This is especially critical for toxoplasmosis where false-positive rates exceed 50%. 1, 4

Pitfall #3: Misinterpreting Positive IgG as Active Infection

• Positive IgG alone indicates past infection or immunity, not active infection requiring treatment. 4
• IgG avidity testing is essential to determine timing of infection when both IgG and IgM are positive. 2

Pitfall #4: Testing Too Early or Too Late

• Amniocentesis for toxoplasmosis PCR should not be performed before 18 weeks gestation and should occur at least 4 weeks after suspected maternal infection to avoid false negatives. 3
• Testing late in pregnancy without early pregnancy results makes timing of infection difficult to determine. 2

---

Age-Related Susceptibility Considerations

• The 16-25 year age group is most susceptible to acute TORCH infections, with odds of CMV IgM positivity (primary infection) decreasing with age. 5
• Younger women may benefit more from preconception counseling about prevention strategies. 4, 5

---

Geographic and Practice Variations

• The United States does not have routine antepartum screening programs for toxoplasmosis, unlike France (monthly screening since 1978) and Austria (screening every trimester since 1975). 2
• In 2006,43% of US obstetricians performed serologic screening for toxoplasmosis in at least some asymptomatic pregnant women, though only 62% used appropriate tests. 2
• Providers in the northeastern United States were twice as likely to routinely screen compared to those in the West. 2