Updated: 2007
QD
Once each day. QID
Four times each day. Quality Assurance
An examination that reviews a study, manufacture of a drug or other process in order to certify that correct methods were followed. Radiology
The science of diagnosis and treatment of disease using radioactive substances, including x-rays, radioactive isotopes, ionizing radiation, and C-T scans. Randomized Trial
A study in which participants are randomly (i.e. by chance) assigned to one of two or more treatment arms or regimens of a clinical study. Occasionally, placebos are utilized. Rapid HIV Test
A screening test for detecting antibody to HIV that produces very quick results, usually in 5 to 30 minutes. For diagnosis of HIV infection, a positive rapid test is confirmed with a second rapid test made by a different manufacturer. Reagent
A substance used in a chemical reaction to detect, analyze, or produce another substance. Rebound
An increase in viral load following a previous decrease due to anti-HIV therapy. Receptor
A molecule on the surface of a cell that serves as a recognition or binding site for antigens, antibodies, or other cellular or immunological components. Referral
A suggestion that a patient see another individual (usually a specialist) for another opinion. Refractory
Referring to a disease that does not readily respond to treatment. Reinfection/Superinfection
The infection of an already HIV-infected person with another strain of HIV. The superinfection can be with a more aggressive strain of HIV. Remission
The lessening in the severity of symptoms or duration of an outbreak of a disease. Renal
Pertaining to the kidneys. Replacement Feeding
The process of feeding a child who is not receiving any breast milk with a diet that provides all the nutrients the child needs. During the first 6 months this should be with a suitable breast-milk substitute--commercial formula, or home-prepared formula with micronutrient supplements. After 6 months it preferably should be with a suitable breast-milk substitute and complementary foods made from appropriately prepared and nutrient-enriched family foods, given three times a day. If suitable breast-milk substitutes are not available, appropriately prepared family foods should be further enriched and given five times a day. Replication
The process of duplicating or reproducing. Rescue Therapy
See
Salvage Therapy. Resistance
Reduction in a microorganism's sensitivity to a particular drug. Resistance is thought to result usually from a genetic mutation. In HIV, such mutations can change the structure of viral enzymes and proteins so that an antiviral drug can no longer bind with them as well as it used to. Resistance Testing
See
Genotype; Phenotype. Resistance Testing
The evaluation of bacteria or viruses such as HIV to determine whether they are resistant to the effects of drugs used for treatment. Resistance testing is an important tool to determine whether a patient with HIV infection is getting sicker because ARV drugs are no longer working. Retina
Light-sensitive tissue at the back of the eye that transmits visual impulses to the brain via the optic nerve. See
Retinitis. Retinal Detachment
Condition in which a portion of the retina becomes separated from the inner wall of the eye. In AIDS patients, it can result from retinal disease such as Cytomegalovirus (CMV) retinitis. Retinitis
Inflammation of the retina, linked in AIDS to Cytomegalovirus (CMV) infection. Untreated, it can lead to blindness. Retrovirus
A type of virus that, when not infecting a cell, stores its genetic information on a single-stranded RNA molecule instead of the more usual double-stranded DNA. HIV is an example of a retrovirus. Reverse Transcriptase
An enzyme capable of copying RNA into DNA during the HIV multiplication cycle. Several anti-HIV drugs--such as AZT, ddI, and ddC--are chemicals that act against the reverse transcriptase enzyme. Reverse Transcriptase Inhibitors (RTI)
A series of nucleoside analogues that inhibit the reverse transcriptase of HIV. Included in this category are the drugs zidovudine, lamivudine, abacavir, didanosine, stavudine, zalcitabine, and emtricitabine. Reverse Transcriptase Polymerase Chain Reaction (RT-PCR)
An FDA-approved test to measure viral load. The test is also known as PCR (polymerase chain reaction). See
Polymerase Chain Reaction (PCR). Rhinitis
Inflammation of the mucous membrane of the nose. Ribonucleic Acid (RNA)
A nucleic acid, found mostly in the cytoplasm of cells (rather than in the nucleus) that is important in the synthesis of proteins. Risk Assessment
Risk assessment is a fundamental part of an HIV prevention counseling session in which the individual is encouraged to identify, acknowledge, and discuss in detail his or her personal risk for acquiring or transmitting HIV. RNA
See
Ribonucleic Acid (RNA). RTI
See
Reverse Transcriptase Inhibitors (RTI). RT-PCR
See
Reverse Transcriptase Polymerase Chain Reaction (RT-PCR). RTV
Ritonavir Rupture of Membranes
Also known as water breaking. A term used to define the rupture of the amniotic sac, releasing the amniotic fluid and heralding the onset of labor. | 
