Lipoprotein-associated phospholipase A2 (Lp-PLA2), also known as platelet activating factor Acetylhydrolase, is an inflammatory enzyme that circulates bound mainly to low density lipoproteins and has been found to be localized and enriched in atherosclerotic plaques.

The LP-IR Score (Lipoprotein Insulin Resistance Score) is a blood test that measures insulin resistance using NMR (nuclear magnetic resonance) spectroscopy analysis of lipoprotein particle sizes and concentrations. The optimal score is less than 25. Scores of 25–45 are borderline; scores above 45 indicate increasing insulin resistance. Unlike fasting glucose or HOMA-IR, the LP-IR Score can detect insulin resistance earlier by measuring the lipoprotein changes that precede blood sugar abnormalities.

Lupus anticoagulants are antibodies against substances in the lining of cells. These substances prevent blood clotting in a test tube.

Luteinizing hormone (LH) is a key reproductive hormone produced by the pituitary gland. In women, LH triggers ovulation and supports progesterone production during the menstrual cycle. In men, LH stimulates the testes to produce testosterone, which is essential for sperm production, libido, and overall reproductive health.

Luteinizing Hormone, Human (hLH), plays a crucial role in the female reproductive system and is a key marker on a female hormone panel. This hormone, produced by the pituitary gland, is involved in regulating the menstrual cycle and ovulation. In the first half of the menstrual cycle, hLH levels gradually increase, leading to a significant surge just before ovulation. This surge is critical as it triggers the release of an egg from the ovary, making it a pivotal moment for fertility. After ovulation, if the egg is not fertilized, hLH levels decrease, and the menstrual cycle continues.

Lyme Ab (IgG) measures immunoglobulin G antibodies produced by the immune system in response to infection with Borrelia burgdorferi, the bacterium that causes Lyme disease. These antibodies typically develop several weeks after infection and may remain detectable for months or even years. A positive Lyme IgG result suggests previous exposure or later-stage infection, while a negative result may indicate no prior infection or testing performed too early in the disease course. This marker is often evaluated together with Lyme IgM antibodies and confirmatory tests to help determine whether symptoms may be related to Lyme disease.

Lyme Ab (IgM) measures immunoglobulin M antibodies produced by the immune system shortly after infection with Borrelia burgdorferi, the bacterium responsible for Lyme disease. IgM antibodies typically appear within the first few weeks following a tick bite and may indicate a recent or active infection. This test is usually interpreted together with Lyme IgG antibodies and clinical symptoms to help determine whether Lyme disease may be present.

Two types of antibodies are detected in the Western blot test.

IgG antibodies are a sign of an older infection. IgM antibodies in contrast reflect a relatively recent infection.

Two types of antibodies are detected in the Western blot test.

IgM antibodies reflect a relatively recent infection. IgG antibodies in contrast are a sign of an older infection.

The two most common diagnostic tests for Lyme are the enzyme-linked immunosorbent assay (ELISA) and the Western blot. Both of these blood tests measure the presence of antibodies that form in your body if you are infected with Borrelia burgdorferi, the bacterium that causes Lyme. This marker is part of the ELISA assay.

This test measures the level of Borrelia antibodies in your blood. Borrelia burgdorferi bacteria cause Lyme disease.

The bacteria are spread to humans through the bite of an infected tick.

Lyme disease is the most common tick-borne illness in the U.S. If not treated, Lyme disease can cause an infection of the tissues covering the brain and spinal cord (meningitis).

The Lyme IgG Line Blot Interp. is a marker used in the diagnosis of Lyme disease. It refers to the interpretation of the results obtained from an IgG immunoblot test used to detect antibodies against Borrelia burgdorferi, the bacterium responsible for causing Lyme disease.