Clinics and Departments

Laboratory Services

Lab Dept:


Test Name:


General Information

Lab Order Codes:



Newborn Torch Titer IgM; Torch Profile IgM

CPT Codes:

86645 – Cytomegalovirus Ab, IgM
86694 – Herpes simplex Ab, IgM
86778 – Toxoplasma Ab, IgM
86762 – Rubella Ab, IgM

Test Includes:

Toxoplasma gondii IgM Antibody; Rubella Virus IgM Antibody; Cytomegalovirus (CMV) IgM Antibody; Herpes Simples Virus (HSV) IgM Antibody


Test Indications:

Screen for serologic response to toxoplasmosis, rubella, CMV, or herpes virus infection; evaluation of possible congenital infection.

Toxoplasma, rubella, cytomegalovirus, and herpes are all causes of potentially catastrophic congenital infections, which can be quickly fatal or lead to chronic sequelae including hepatitis, encephalitis, and failure to thrive. In the fulminant case serologic diagnosis is of little use since the disease outstrips the immune response and even IgM antibody cannot be demonstrated in time to be clinically useful. However, in the disease which becomes manifest weeks to months after birth, demonstration of IgM antibody or rising titers of IgG antibody can confirm a diagnosis of specific infection. The presence of IgM-specific antibody in cord, fetal, or neonatal blood indicates congenital infection. It should be emphasized that TORCH testing is of very limited usefulness. Results must be interpreted in conjunction with complete clinical information, and such testing in no way substitutes for careful clinical examination and judgment. TORCH testing should not be applied indiscriminately to pregnant women or infants with nondescript illnesses. See individual listings.

Lab Testing Sections:

Serology - Sendouts

Referred to:

Mayo Medical Laboratories (Test: TRCHM) for Toxplasma gondii IgM, CMV IgM, HSV IgM

Lab Corp (Test: 096537) for Rubella IgM

Phone Numbers:

MIN Lab: 612-813-6280

STP Lab: 651-220-6550

Test Availability:

Daily, 24 hours

Turnaround Time:

1 – 3 days, test set-up Monday - Saturday

Special Instructions:

Collect specimen as soon as possible after onset of illness and no later than 5 - 7 days.


Specimen Type:



Red top (plain, no gel) tube

Draw Volume:

Draw 2 tubes:

3 mL (Minimum: 2.7 mL) blood for Mayo
3 mL (Minimum: 1.5 mL) for Lab Corp

Processed Volume:

1 mL (Minimum: 0.9 mL) serum for Mayo
1 mL (Minimum: 0.5 mL) for Lab Corp


Routine blood collection

Special Processing:

Lab Staff: Centrifuge specimen, remove serum aliquots into two screw-capped round bottom plastic vials, one for Mayo and one for Lab Corp. Store and ship at refrigerated temperatures. Forward promptly.

Patient Preparation:


Sample Rejection:

Excessive hemolysis; chylous serum; gross specimen contamination


Reference Range:

Toxoplasma IgM Ab:




0.55 – <0.65



Rubella IgM Ab


<0.9 index


0.9 – 1.0 index


>1.0 index

The presence of IgM class Ab indicates congenital or recent infection.

Cytomegalovirus IgM Ab: Negative

Note: Reported as positive, equivocal, or negative. The presence of IgM class antibodies indicates recent infection.

Herpes simplex IgM Ab (IFA): Negative

Note: Reported as positive or negative.

Critical Values:



Negative serologic results do not exclude infection.


Toxoplasma gondii IgM: Enzyme-linked Fluorescence Assay (EFLA)
Rubella virus IgM: Chemiluminescence
Cytomegalovirus IgM: Multiplex Flow Immunoassay (MFI)
Herpes Simplex Virus IgM: Immunoflourescence Assay (IFA)


Mayo Medical Laboratories Web Page June 2013
Lab Corp
June 2013


3/4/2004: Test moved from Lab Corp (Viromed) to MML (forward to Focus Technologies).
7/29/2004: Test no longer forwarded to Focus Technologies. All testing done at MML.
7/10/2007: HSV IgM screening test by EIA will be performed initially and if positive will reflex to the IFA test.
8/13/2007: HSV IFA reinstated as primary test for this testing. No reflex is necessary for it to be performed.
7/1/2008: Rubella IgM is no longer performed at MML. Test moved to MDH. Orderable split between Mayo and MDH.
12/19/2012: Moved from MDH to Lab Corp.
6/11/2013: CMV method update at MML from ELFA to MFI.

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