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Herpes Simplex Virus Type 1 Immunoglobulin M Antibody (IgM) in Serum/Plasma

Published: August 9, 2026Updated: August 16, 2026

This test detects antibodies to the herpes simplex virus type 1 (HSV-1), which can help identify past or recent infection with this virus.

Quick summary

["This test helps determine if you may have been exposed to HSV-1 recently or in the past."]

Medically reviewed by WellAlly Editorial TeamLast reviewed August 16, 2026Editorial policy

Key facts at a glance

LOINC
110919-8
Short code
HSV1 IgM Msmt CSF
Synonyms
HSV1 IgM Msmt CSF
Category
chemistry
Sample
csf
Container
Sterile tube
Units
N/A
Fasting
false
Population
adult
Sex
all
Age range
18–65 years
CPT
82784
Specimen volume
1-2 mL
Stability
Immediate analysis required, Refrigerated: 1h
Hemolysis max
200
TAT
4–24 hours
Order
routine

What This Test Measures

The test looks for IgM antibodies specific to HSV-1 in your blood. IgM antibodies are typically produced shortly after infection and can indicate an acute (recent) infection. They usually decline over time as your body produces other types of antibodies (IgG).

Why It Might Be Ordered

Your healthcare provider may order this test if you have symptoms like fever, mouth sores, or genital sores that suggest HSV-1 infection, or if you’ve been exposed to someone with HSV-1. It can also be used to monitor certain conditions or after exposure to confirm infection status.

What to Expect Before the Test

No special preparation is needed for this blood test. You may have a small needle inserted into your arm to draw blood. If you’re pregnant, breastfeeding, or have a bleeding disorder, let your provider know before the test.

What to Expect During the Test

The blood sample is taken from a vein in your arm. You may feel a slight pinch or discomfort, but it usually lasts only a few seconds. The test itself takes only a few minutes, and you can resume normal activities afterward.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

◆Associated findings1

Short name

HSV-1 IgM Antibody

Frequently asked questions

How long does it take to get results from this test?
Results are typically available within 1 to 3 business days, depending on your lab’s processing schedule. Your healthcare provider will discuss the results with you during your follow-up visit.
Can HSV-1 IgM antibodies be positive if I’ve had the virus for a long time?
Yes, IgM antibodies can remain detectable for months or even years after an initial infection, though their levels often decline over time. IgG antibodies, which develop later, are usually more reliable for confirming past infection.
Does this test differentiate between HSV-1 and HSV-2?
No, this test only detects antibodies to HSV-1. If you suspect HSV-2 infection, a separate test for HSV-2 antibodies would be needed.
  1. 1
    MedlinePlus — Laboratory TestsSource
  2. 2
    Lab Tests OnlineSource
  3. 3
    Mayo Clinic — Tests & ProceduresSource

Click any link to access the full source. PubMed Central (PMC) links provide free full-text access.

This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.

Medical Disclaimer

This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.

If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.

Medically reviewed by WellAlly Editorial Team Last reviewed August 16, 2026. · Read our editorial policy