Borrelia burgdorferi IgM Antibody Test for Early Lyme Disease Diagnosis

公開:2026年8月9日更新:2026年8月15日

This blood test detects IgM antibodies against Borrelia burgdorferi, the bacteria that causes Lyme disease, helping diagnose early infection after a tick bite.

クイックサマリー

["\"「この検査はIgM抗体を検出し、ライム病の初期感染を調べます」\",\n \"「陽性の結果は、チクセンゴクに咬まれてから3～4週間以内に感染が疑われる場合に出ます」\",\n \"「陽性の結果は、通常、二段階の検査（ウェスタンブロット）で確認されます」\",\n \"「チクセンゴクに咬まれてから3～4週間経過した後に検査することが最も精度が高い」\",\n \"「早期の検査と治療により、より良い治療結果が期待できます」\"\n },\n \""]

WellAlly編集チームが医学的にレビュー済み最終レビュー日：2026年8月15日編集方針

要点一覧

LOINC: 101149-3
略号: LYME-IGM
類義語: B burgdor IgM Index Ser+CSF-aCnc
カテゴリ: 生化学
検体: serum
容器: Serum separator tube (SST) for serum; sterile CSF collection tube for cerebrospinal fluid
単位: N/A
基準値下限: 0
基準値上限: 0.8
絶食: false
対象集団: 成人
性別: all
年齢範囲: ≥ 0 歳
検査方法: Enzyme-linked immunosorbent assay (ELISA) or Chemiluminescent Immunoassay (CLIA) for qualitative/quantitative detection of IgM antibodies against Borrelia burgdorferi, typically followed by Western blot confirmation
CPT: 86617 (Borrelia burgdorferi antibody, IgM); 86618 (Borrelia burgdorferi confirmatory Western blot)
SNOMED: 397575002 |Borrelia burgdorferi immunoglobulin M antibody measurement|
検体量: 0.5-1 mL serum and/or 0.5-1 mL CSF
安定性: Serum stable at room temperature for 8 hours, refrigerated (2-8°C) for 7 days, frozen at -20°C or below for long-term storage. CSF should be processed and stored similarly with analysis ideally within 24-48 hours.
溶血（最大）: 100
脂肪血症（最大）: 100
黄疸（最大）: 50
TAT: 24–72 時間
検査依頼: routine

What is this test?

The Borrelia burgdorferi IgM Antibody test is a blood test that checks for IgM (immunoglobulin M) antibodies against the bacteria that cause Lyme disease. When a tick carrying Borrelia burgdorferi bites you, your immune system responds by producing IgM antibodies first. These antibodies typically appear within 2-3 weeks of infection and are the earliest sign that your body is fighting the bacteria.

Why might I need this test?

Your healthcare provider may order this test if you have symptoms of early Lyme disease, especially if you have recently been bitten by a tick or spent time in areas where Lyme disease is common. Early symptoms may include a expanding red rash (erythema migrans), fever, headache, fatigue, and muscle aches. The test is most useful when performed 3-4 weeks after potential exposure, as this allows enough time for antibodies to develop.

How is the test performed?

A healthcare professional will draw a small blood sample from a vein in your arm. The sample is then sent to a laboratory where technicians look for IgM antibodies against Borrelia burgdorferi. Results are typically reported as an index value, with values above a certain threshold considered positive or borderline.

What do the results mean?

"「結果は通常、指数値で報告されます」", "「閾値以下の場合は陰性と判定され、IgM抗体が検出されません」", "「閾値に等しいまたは以上の場合は陽性または疑いの結果となり、ライム病の早期感染が疑われます」", "「IgM陽性の結果は、通常、ウェスタンブロット検査で確認する必要があります。CDCが推奨するライム病の標準二段階検査法です」" }, "

Are there any limitations?

"「感染初期（感染後2～3週間以内）では、抗体が検出されない場合があり、偽陰性の結果となる可能性があります」", "「治療に成功した後でも、IgM抗体が長期間残ることがあり、この検査は治療効果を監視するために使用されません」", "「他の類似感染症との交叉反応により、偽陽性の結果となることがあります」" }, "

Reference range

Negative: <0.80 Index (antibody index); Equivocal: 0.80-1.00 Index; Positive: >1.00 Index. Reference ranges vary by laboratory and assay manufacturer. Results should be interpreted alongside clinical findings and confirmatory Western blot testing.N/A

検体: serum

No special patient preparation required. Fasting is not necessary for this serological test.

Clinical interpretation

How abnormal results are interpreted and what conditions they suggest.

よくある質問

Does a positive result mean I definitely have Lyme disease?

Not necessarily. A positive IgM result indicates that your immune system has produced antibodies against Borrelia burgdorferi, which suggests infection. However, the test result should be interpreted by your healthcare provider along with your symptoms, exposure history, and often confirmed with additional testing (Western blot). False positives can occur due to cross-reactivity with other conditions.

How long after a tick bite should I wait to get tested?

It is generally recommended to wait at least 2-4 weeks after a tick bite before getting tested. This allows enough time for your body to develop detectable antibodies. Testing too early may give a false negative result. If you develop symptoms like the characteristic bull's-eye rash, contact your healthcare provider immediately even if testing is not yet recommended.

Can this test tell me if I'm cured after treatment?

No, this test is not used to monitor treatment success. After successful antibiotic treatment, IgM antibodies may remain detectable for months or even years. Therefore, follow-up testing to check antibody levels is not recommended. Your healthcare provider will determine treatment success based on your symptoms improvement, not blood test results.

What is the difference between IgM and IgG tests?

"「IgM抗体は感染初期に作られる最初の抗体で、感染後2～3週間で出現します」", "「IgG抗体は感染後4～6週間で出現し、長期間体内に残る」", "「IgM検査はライム病の早期診断に適しています。一方、IgG検査は感染が進行した場合や過去の暴露を検出するのに適しています」" }, "

Is the test painful?

The test involves a standard blood draw, which may cause brief discomfort or a slight sting when the needle is inserted. The procedure typically takes only a few minutes. Some people may experience minor bruising or soreness at the puncture site afterward, but serious complications are rare.

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医療に関する免責事項

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医学的緊急情况可能性があると思われる場合は、すぐに現地の緊急連絡先に電話するか、最寄りの緊急治療室に直行してください。

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