14.1

• Diurnal variation refers to the normal daily fluctuations in body chemistry related to hormonal cycles, sleep–wake cycles, and

  other regular patterns of change.
• The basal state is defined as the body’s state after 8 to 12 hours of fasting and abstention from strenuous exercise.
• Caffeine-and-nicotine are also prohibited during the fasting period, as these are metabolic stimulants.
• Often, the physician will reschedule the lab work, particularly if a lipid profile is ordered.
• The 2-hour postprandial test is used to test for diabetes mellitus.
• OGTT tests for both diabetes mellitus and other disorders of carbohydrate metabolism.
• Hyperglycemia, or abnormally elevated blood sugar, is most commonly caused by diabetes;
• hypoglycemia, or abnormally lowered blood sugar, may be due to one of several endocrine disorders or other metabolic disruptions.
• Longer testing periods are sometimes used as well to identify a

  variety of metabolic disorders.
• Glucose tolerance testing is still widely used in pregnant women, to diagnose gestational diabetes.
• Gestational diabetes is insulin-resistant diabetes that develops in almost 20% of women late in pregnancy.
• The initial screen (gestational) is a 1-hour GTT, performed without fasting.
• Testing begins between 0700 and 0900 with the collection of a fasting blood specimen and sometimes a urine specimen.
• The pregnant then drinks a standardized amount of glucose solution within 5 minutes.
• The epinephrine tolerance test determines the patient’s ability to mobilize glycogen from the liver.
• glycogen is converted to glucose and released into the bloodstream.
• The test begins with a fasting specimen, followed by the epinephrine injection administered by the physician.
• Specimen collection begins 30 minutes later. EPinephrine
• The glucagon tolerance test is identical in purpose and procedure, except that the hormone glucagon is injected instead of epinephrine.
• The lactose tolerance test (LTT) determines whether the lactose-digesting enzyme lactase is present in the gut.
• the margin of safety or the difference between the level at which a drug is therapeutic and the level at which it becomes toxic, may be narrow.
• Drugs with long half-lives, including digoxin, often require only one timed specimen.
• Drugs with short half-lives, such as the aminoglycoside antibiotics equire the most careful monitoring.
• Monitoring for these rapidly metabolized antibiotics is done with a pair of specimens, known as a peak and a trough.
• The trough level is the lowest serum level and occurs immediately before the next dose of medicine is

  given.
• The peak level occurs sometime after the dose is given; exactly when depends on the characteristics of the drug, the patient’s own metabolism, and the method of administration.
• Most drugs (TDM) need to be collected in a red top tube because the gel in a serum separator tube interferes with the analysis of the drugs.
• Bacteremia refers specifically to the presence of bacteria in the

  blood.
• Septicemia is a life-threatening infection caused by rapid multiplication of pathogens in the bloodstream.
• When microorganisms in the blood trigger a systemic inflammatory

  response, it is called sepsis.
• Patients with symptoms of chills and fever, or fever of unknown origin
• BCs are ordered as stat.
• contain activated charcoal, which absorbs antibiotics from the patient’s blood so that they do not inhibit growth of the bacteria in the culture tube.
• When using a syringe, collect the anaerobic sample first
• Blood donation is a vital link in the health care system, and the phlebotomist plays a central role in the collection of donated blood.
• Guidelines for uniform collection procedures and safeguards have been established by the American Association of Blood Banks
• times. A patient can donate as often as every 72 hours, assuming that his or her health is good.
• Hemoglobin is checked during the donation series and should not fall below 11 g/dL.
• Therapeutic phlebotomy is the removal of blood from a patient’s system as part of the treatment for a disorder.
• polycythemia, a disease characterized by excessive production of red blood cells