Following a thorough health history and physical examination, the doctor orders lab tests to help confirm or rule out disease conditions. Laboratory tests are used in conjunction with hands-on examinations (B). Class time and internship time is the opportunity to practice skills learned in school (C). Laboratory testing usually requires a substantial budgetary allotment (D) from the office including testing supplies, equipment, and trained personnel. Lack of confidence (E) is a common problem with new graduates, especially in the arena of laboratory testing.
The correct pH of urine is between 4.5 and 8. A pH of 0–1 (A) and 1–3 (B) are too acidic for a normal pH of urine. A pH of 9–11 (D) and 12–14 (E) are too basic or alkaline for a normal pH of urine.
Uncontrolled diabetes mellitus will result in a fruity smell to urine due to excretion of acetone (a type of ketone) from the lungs. Diabetes insipidus (B) does not cause any change to body or urine odor. Urinary tract infection (C) can cause the urine to have a foul smelling odor. Starvation (D) does not cause any change to body or urine odor, but can lead to fat metabolism and the accumulation of ketone bodies in the body tissue. Liver failure (E) can produce a musty smelling urine sample.
Ketones are by-products of fat metabolism. Urea and creatinine are by-products of protein metabolism (A). Monosaccharides are by-products of sugar (B) and carbohydrate (D) metabolism. Many items can result from cellular metabolism (E).
The area between the skin and bone in the finger or the hand is too small in infants and puncturing with a lancet can cause injury to bone. Gravity (A) can help with blood flow despite the area of puncture. Infants are unaware regardless of the procedure (B) and the lancet is usually a concealed semiautomatic blade. Blood flow in the heel of the foot is usually ample if the puncture is substantial (C). Higher concentration of hemoglobin (D) was found in the earlobe; therefore, this site is not utilized any longer.
OSHA standards state that needles and other sharps should be placed in a biohazard sharps container. Vials of blood (B) should be placed in a biohazard container. Used syringes (C) should be placed in the biohazard sharps container if there is a used needle or in a biohazard container if no needle is present but has been exposed to medication or bodily fluid. Blood-stained gloves (D) should be placed is a biohazard container. Wearing a lab coat and mask when taking vital signs (E) is unnecessary.
Red blood cells (A) are heavy elements that will move to the bottom of the centrifuged sample of blood. Bacteria (C) should not be found in a blood sample. When blood is centrifuged, it forms into striated layers, from top to bottom: plasma, buffy coat, and red blood cells. Plasma (D) is the top layer. Platelets (B) and white blood cells are included in the buffy coat. Serum (E) is plasma from which the clotting factor fibrinogen has been removed.
The typical range for needles used in venipuncture is 20–22 gauge. Gauge 13–15 (A) needles are too large for most superficial veins. Gauge 15–19 (B) needles are also too big for venipuncture, but may be used for intramuscular injections. Gauge 19–21 (C) includes needles that are still too large for comfortable phlebotomy procedures. Gauge 23–25 (E) needles are smaller. Butterfly winged infusion sets may have 23-gauge needles.
Total magnification is calculated using the following formula: 10× (ocular) 40× (lowest objective) = 400× (total magnification of the viewed object). Magnification of 10× (A) is the strength of the eyepieces and the low power objective. Magnification of 40× (B) is the strength of the high power objective. Magnification of 100× (C) is the strength of the oil immersion objective. Magnification of 1000× (E) is the total magnification when using the oil immersion and the eyepieces.
Yellow is always first if a sterile specimen must be obtained, e.g., blood culture (prevents contamination from other tubes and additives). Blue, for coagulation studies, comes next. Red, for serum tubes with no additives, comes after that. Tiger (red/gray) contains a serum separator and is silicone, so would not contaminate other tubes; it should be drawn next.
Since people typically drink little at night and urinate less frequently at night, the first morning specimen contains a higher concentration of dissolved substances; thus it should be used when testing for pregnancy. A false negative pregnancy test, especially early in pregnancy, may occur if the patient has drunk a lot of fluids, which dilutes the urine. If a patient is unable to void immediately when in the office (B), the staff typically will offer water and have the patient wait until able to provide a specimen for testing. Although a first morning specimen may be used to screen for an infection (C), a sterile, clean-catch, midstream specimen freshly obtained in the office is desired for accuracy. The clean-catch midstream technique can be used at any time of day (D). Although the specimen could be used as a baseline for a later comparison, this is not the principal reason for collecting it.
If the patient has a boiled jar it can be used to collect a midstream specimen. Washing (A and B) does not remove all the germs in a jar. Before voiding, the patient should cleanse three separate times from front to back (not back to front, D) on each side of the urethral opening and then down the middle. The urine should be collected in the middle of the stream. This is because the first part of the stream will cleanse the urethra, and the end of the stream could contain residual sediment from the bladder. Although commercial sterile container is preferable, and it is likely that the provider will want a fresh specimen taken in the office, a sample taken at home is valid if properly collected (E) and may help determine what additional testing is necessary.
Although not a definitive diagnosis, glucose in the urine calls for further laboratory testing for diabetes. (Other clues are increased thirst and increased frequency of urination.) Ketones are a result of fat breakdown; in uncontrolled diabetes, a person’s metabolism often breaks down fat for energy at a faster rate than average, spilling ketones into the urine. Glucose and ketones in urine are not normal (A). Infection (C) would likely be indicated by positive nitrites in the urine screening, not glucose. Patients with kidney damage (D) will likely have protein in their urine (i.e., albuminuria or proteinuria) as a result of the excessive stress on the kidneys, but not ketones. A patient who is experiencing excessive vomiting or anorexia nervosa (E) may spill ketones into the urine as a result of fat breakdown, but not glucose.
The FBS is a chemistry test, and the patient can drink water but should avoid some medications such as aspirin, diuretics, and steroids for several days prior to the blood draw. Although FBS is a good indicator of diabetes, it is not a definitive test; additional testing would still be warranted. Hematology tests (B) involve testing the cellular part of the blood; FBS is a chemistry test. A 2-hour postprandial test (C) may be ordered to aid diabetes diagnosis, but the specimen collected for this test is urine, not blood. The blood sample tested in FBS cannot be collected via capillary puncture (D) because this method would not provide enough blood for testing, and also because venous blood provides a more representative specimen of the amount of glucose circulating in the bloodstream. Normal blood sugar levels are in the range of 70–100 mg/dL; 120 mg/dL (E) is too high to rule out diabetes.