- lactate
Another
name for lactic acid.
- lactic acidosis
High blood levels of lactic acid, a substance involved in metabolism. If untreated, can be fatal.
- lesion
Any
abnormal change in body tissue caused by disease or injury. Often refers to
Kaposi's sarcoma, which can cause skin lesions.
- leukocytes
White
blood cells.
- leukopenia
Fewer
than normal white cells in the blood, usually due to bone marrow damage.
- libido
Another
word for sexual drive.
- limit of detection
The lower limit of detection is a standard measure for a test procedure. It describes the lowest concentration which can still be detected by the test system.
- lipid
A
general term for fats.
- lipoatrophy
Loss
of body fat.
- lipodystrophy
A
disruption to the way the body produces, uses and distributes fat.
- liver
An essential organ with hundreds of functions, including filtering chemicals and waste from the blood; storing vitamins, minerals, and iron; converting nutrients from food into energy; helping to balance levels of sugar and hormones; producing cholesterol; making bile (necessary for digestion); and creating the hormone that helps blood to clot (to stop bleeding).
- liver enzymes
Proteins that help to speed up chemical reactions in the body. Inflamed liver cells leak higher than normal amounts of liver enzymes into the bloodstream, detected by blood tests.
- liver function tests (LFTs)
Tests
evaluating the functioning of the liver.
- liver toxicity
Drug side-effects affecting the liver.
- L-lactate dehydrogenase (LD)
LD is an enzyme found in the liver. Elevated levels may indicate liver damage.
- log
Short
for logarithm, a scale of measurement often used when describing viral load. A
one log change is a ten-fold change, such as from 100 to 10. A two log change
is a one hundred-fold change, such as from 1,000 to 10.
- longitudinal study
A
study in which information is collected on people over several weeks, months or
years. People may be followed forward in time (a prospective study), or
information may be collected on past events (a retrospective study).
- loss to follow up
In a research study, participants who drop out before the end of the study. In routine clinical care, patients who do not attend medical appointments and who cannot be contacted.
- lumbar puncture
A
small hole made in the spinal column to take out spinal fluid for tests or to
inject drugs. Also called a spinal tap. It involves the insertion of a needle
through the tissue between the vertebrae to access the spinal canal.
- lymph nodes
Bean-sized structures throughout the body's lymphatic system, where immune cells
congregate to fight infections.
- lymphadenopathy
A
swelling of the lymph nodes.
- lymphocyte
A
type of white blood cell.
- lymphoid tissue
Tissue
involved in the formation of lymph fluid, lymphocytes and antibodies.
- lymphoma
A
type of tumour affecting the lymph nodes.