Chapter 34: Diagnostic Testing
Mr. Brown is admitted with advanced liver disease. Which of the following lab results would you expect to see? a. Albumin 2.6 g/dL b. Blood urea nitrogen 18 mg/dL c. Homocysteine 2.4 mg/L d. Bilirubin 0.7 mg/dL
ANS: A A decreased albumin level is commonly found in patients with liver disease. Blood urea nitrogen is used to evaluate and monitor renal function. Homocysteine indicates risk of cardiovascular disease. The bilirubin level given is normal; the bilirubin level is elevated in advanced liver disease.
Mr. Grant has just had a lumbar puncture. Which of the following notes would be important to document on his plan of care? a. He is to lie flat for at least 4 hours. b. He should remain NPO for at least 4 hours. c. The nurse should assess for signs of postprocedure hypertension. d. The nurse should hold all sedatives and narcotics for at least 4 hours.
ANS: A Laying flat for the first 4 hours allows the cerebrospinal fluid to shift and prevents post lumbar puncture headaches. It is important to encourage fluids to reestablish normal fluid balance. A lumbar puncture has no effect on blood pressure. There is no reason to withhold analgesics, especially in situations where the patient is complaining of a headache.
You are instructing Miss Ford on a sterile urine collection. Which statement would indicate the need for further instruction? a. "I separate the folds and clean from back to front." b. "I clean the area three times." c. "I begin the urine stream and then place the container under the stream midway through." d. "I make sure there is no stool in the urine specimen."
ANS: A The proper cleansing direction is front to back to prevent any contamination of the urethral area from the rectum. Cleaning the area three times minimizes the chances of contaminating the urine specimen from normal flora contained on the skin. Allowing the first part of the stream to pass before collecting the urine flushes the urethral tract of possible contaminants. Any fecal matter will contaminate the results of the urine tests.
Which of the following allergies would be problematic for a patient scheduled for computed tomography with contrast? a. Allergy to penicillin b. Allergy to shellfish c. Allergy to peanuts d. Allergy to latex
ANS: B Many of the contrast mediums used in computed tomography contain iodine. Patients who are allergic to shellfish are commonly sensitive to iodine and may experience an allergic reaction to the contrast medium. Allergies to peanuts, penicillin, and latex would not contraindicate computed tomography with contrast.
Mr. Newman has been admitted to the emergency room with a diagnosis of acute myocardial infarction (heart attack) within the past 2 hours. Which of the following cardiac markers would you expect to be elevated at this point? a. CK-MB b. Myoglobin c. Troponin I d. TroponinT
ANS: B Myoglobin is released within the first 2 hours after a myocardial infarction. The levels of CK-MB, troponin I, and troponin T begin to rise within the first 3 hours after a myocardial infarction.
Which of the following blood tests requires the patient to be fasting? a. Hemoglobin b. Prothrombin time c. Cholesterol d. Creatinine
ANS: C Cholesterol levels should be drawn after an 8- to 12-hour fast. Tests for hemoglobin level, prothrombin time, and creatinine level do not require fasting.
You are explaining a paracentesis to Mrs. Jackson. Which of the following statements would be incorrect? a. "You will need to sign a consent form before the procedure." b. "We will be using a needle to remove fluid from your abdomen." c. "I will be measuring your abdomen before and after the procedure." d. "You will be lying on your left side during the procedure."
ANS: D For a paracentesis, the patient should be in a high Fowler or sitting position. This is an invasive procedure, so informed consent is required. A needle is used to remove excess fluid from the peritoneal space. It is important to measure the abdominal girth before and after the procedure to evaluate patient response to the procedure.
Mrs. Jackson is a 58-year-old woman with no family history of colorectal cancer. Which of the following screening guidelines would you recommend? a. Fecal occult blood testing every 5 years b. Sigmoidoscopy every 10 years c. Cystoscopy every 5 years d. Colonoscopy every 10 years
ANS: D For people over the age of 50 with no family history, a colonoscopy is recommended every 10 years. Fecal occult blood testing is suggested every year; sigmoidoscopy is suggested every 5 years. A cystoscopy is used to evaluate the bladder and urethra.
Which specimens should be collected using sterile technique in a sterile container? (Select all that apply.) a. Clean-catch urine b. Stool for occult blood c. Wound drainage d. Sputum e. Urine from a Foley catheter
Answer: a, c, d, e Clean-catch urine, urine from a Foley catheter, wound drainage, and sputum should be collected using sterile technique and in sterile containers. All are collected to determine presence of bacteria or infection. A stool for occult blood does not need to be sterile; a stool for culture needs to be collected in a sterile container.
The patient states that she has been taking Coumadin, an anticoagulant, for several years. The nurse notices several bruised areas on her arms. Which of the following laboratory results is clinically significant? a. Platelets: 450,000 b. Prothrombin time: 24.2 seconds c. Activated partial thromboplastin time: 30 seconds d. Fibrinogen: 350 mg/dL
Answer: b An increased prothrombin time indicates prolonged bleeding times. Coumadin increases prothrombin times, and bruising is a physical indicator of increased bleeding. Therapeutic doses of Coumadin increase the prothrombin time to 1.5 to 2 times that of the control group. Increased platelet counts are not responsible for bruising. The activated partial thromboplastin time and fibrinogen results are within normal ranges.
Which laboratory result should immediately be reported by the nurse to the primary care provider? a. Hemoglobin: 15.6 b. Hematocrit: 32% c. Red blood cells: 5.3 d. White blood cells: 6000
Answer: b Normal hematocrit levels range from 42% to 52% for males and 37% to 48% for females. The results for the hemoglobin, red blood cell, and white blood cell tests are within normal ranges.
The nurse is working at a health fair and providing information about reducing the risk of heart disease. A male asks what his ideal numbers should be for cholesterol and triglycerides. Which of the following is correct? a. Total cholesterol: >200 mg/dL b. HDL: >45 mg/dL c. LDL: >100 mg/dL d. Triglycerides: >160 mg/dL
Answer: b Recommended levels for high-density lipoprotein (HDL) cholesterol are >45 mg/dL for males; >55 mg/dL for females. Total cholesterol level of less than 200, low-density lipoprotein (LDL) cholesterol level of less than 130 mg/dL, and triglyceride levels of less than 160 mg/dL for males and <135 mg/dL for females are normal values.
Which blood test is used to monitor renal function? a. Creatine kinase b. Triglycerides c. Creatinine d. Alkaline phosphatase
Answer: c Creatinine is a by-product of skeletal muscle metabolism and is excreted by the kidneys. It is released from the muscles at a consistent rate, and blood levels give an accurate reflection of renal filtration. Creatine kinase is released during cardiac, skeletal, or brain cell damage. Triglycerides reflect dietary intake and risk of cardiovascular disease. Alkaline phosphatase provides information about liver function.
For which patient is magnetic resonance imaging contraindicated? a. A patient with an allergy to latex b. A patient with an infection c. A patient with a pacemaker d. A patient with a head injury
Answer: c Pacemakers normally contain metal and can be pulled out of position by the strong magnetic force generated in magnetic resonance imaging. Latex allergy, infection, and head injury are not contraindicated.
The patient tells the nurse that she has been on a high-protein, low-carbohydrate diet for the past 6 months. Which blood test results could be influenced by her diet? a. Bilirubin b. Creatinine c. Blood urea nitrogen d. Creatine kinase
Answer: c Urea is a by-product of protein metabolism, and the blood urea nitrogen level can be influenced by high protein diets. Bilirubin is a by-product of hemolysis; creatinine is a by-product of skeletal muscle metabolism; creatine kinase is an enzyme found in muscle and brain tissues. None of them is influenced by diet.
The nurse is attempting a fingerstick on a diabetic patient and is having difficulty obtaining a suitable drop of blood. Which intervention may facilitate this process? a. Applying a tourniquet above the hand b. Asking the patient to close and open her hand several times c. Applying warm compresses d. Elevating the hand on a pillow
Answer: c Warm compresses applied to the hand cause vasodilation of the veins in the fingers, increasing the size of the blood drop needed for a fingerstick examination. Applying a tourniquet and asking the patient to open and close the hand facilitate vein enlargement for venipuncture. Elevating the hand on a pillow reduces blood flow to the fingers and makes it more difficult to obtain an adequate blood drop.
A patient is ordered a 24-hour urine specimen for creatinine clearance. Which instruction is correct? a. "Collect all urine from the time the collection begins until it ends." b. "Save only a sample from each voiding." c. "Clean the perineal area three times each time before you begin to urinate." d. "Discard the first urine specimen, and then collect all urine until the time period expires."
Answer: d Discarding the first void ensures that the test begins with fresh urine specimens. The patient needs to save all urine from the beginning of the collection period until the end. Because this does not require a sterile specimen, the cleansing process is not needed.
The nurse is preparing a patient for an esophagogastroduodenoscopy (EGD). Which statements by the patient indicate that the patient has understood the nurse's teaching? (Select all that apply.) a. "The doctor will be able to view my stomach during the test." b. "I will be able to have something to drink immediately after the test." c. "There are no risks involved with this test." d. "The doctor will be able to see whether there is an ulcer in my stomach." e. "I will be NPO for 8 hours before the test."
Answers: a, d, e The doctor will be able to view the esophagus, stomach, and upper duodenum during an EGD. Ulcers, tumors, and diverticula can be visualized during the test. The patient will receive nothing by mouth (NPO) for 8 hours before the test so that the stomach is empty. The patient will not be allowed to drink after the test until the gag reflex returns. Risks involved with EGD are perforation, bleeding, aspiration, and infection.
