Lab Values Quiz (14 Practice Questions)

Answer & Rationale.

Option 2 is correct.

Rationale: The normal PT is 9.6 to 11.8 seconds (male adult) or 9.5 to 11.3 seconds (female adult). A therapeutic PT level is 1.5 to 2 times higher than the normal level. Because the value of 35 seconds is high (and perhaps near the critical range), the nurse should anticipate that the client would not receive further doses at this time. Therefore the prescriptions noted in the remaining options are incorrect.

Test-Taking Strategy: Focus on the subject, a PT of 35 seconds. Recall that the normal PT is 9.6 to 11.8 seconds (male adult) or 9.5 to 11.3 seconds (female adult) and that a therapeutic PT level is 1.5 to 2 times higher than the normal level. Remember that a PT greater than 30 seconds places the client at risk for bleeding; this will direct you to the correct option.

Answer & Rationale.

Options 2 is correct answer

Rationale: The normal therapeutic range for digoxin is 0.5 to 2 ng/mL. A level of 2.4 ng/mL exceeds the therapeutic range and indicates toxicity. The nurse should notify the HCP, who may give further prescriptions about holding further doses of digoxin. The option that indicates to record the normal value on the client’s flow sheet is incorrect because the level is not normal. The next dose should not be administered because the serum digoxin level exceeds the therapeutic range. Checking the client’s last pulse rate may have limited value in this situation. Depending on the time that has elapsed since the last assessment, a current assessment of the client’s status may be more useful.

Test-Taking Strategy: Note the strategic word immediate. To choose correctly, you must be familiar with the therapeutic range for this medication and note that the level of 2.4 ng/mL is a toxic one. This will direct you to the correct option.

Answer & Rationale

Option 2 is correct answer.

Rationale: The normal blood urea nitrogen level is 8 to 25 mg/dL. Values of 29 mg/dL and 35 mg/dL reflect continued dehydration. A value of 3 mg/dL reflects a lower than normal value, which may occur with fluid volume overload, among other conditions.

Test-Taking Strategy: Focus on the subject, adequate fluid replacement and the normal blood urea nitrogen level. The correct option is the only option that identifies a normal value.

Answer & Rationale.

Option 3 is correct answer.

Rationale: Troponin is a regulatory protein found in striated muscle. The troponins function together in the contractile apparatus for striated muscle in skeletal muscle and in the myocardium. Increased amounts of troponins are released into the bloodstream when an infarction causes damage to the myocardium. A troponin T value that is higher than 0.1 to 0.2 ng/mL is consistent with a myocardial infarction. A normal troponin I level is lower than 0.6 ng/mL.

Test-Taking Strategy: Note that the subject of the question relates to troponin T. Knowing the normal level and that a level higher than 0.1 to 0.2 ng/mL is consistent with a myocardial infarction will direct you to the correct option.

Answer & Rationale

Option 4 is correct answer.

Rationale: The normal aPTT varies between 20 and 36 seconds, depending on the type of activator used in testing. The therapeutic dose of heparin for treatment of deep vein thrombosis is to keep the aPTT between 1.5 and 2.5 times normal. This means that the client’s value should not be less than 30 seconds or greater than 90 seconds. Thus the client’s aPTT is within the therapeutic range and the dose should remain unchanged.

Test-Taking Strategy: Focus on the subject, the expected aPTT for a client receiving a heparin sodium infusion. Remember that the normal range is 20 to 36 seconds and that the aPTT should be between 1.5 and 2.5 times normal when the client is receiving heparin therapy. Simple multiplication of 1.5 and 2.5 by 20 and 30 will yield a range of 30 to 90 seconds. This client’s value is 65 seconds.

Answer & Rationale.

Option 1 is correct answer.

Rationale: The normal serum potassium level in the adult is 3.5 to 5.0 mEq/L. The correct option is the only value that falls below the therapeutic range. Administering furosemide to a client with a low potassium level and a history of cardiac problems could precipitate ventricular dysrhythmias. The remaining options are within the normal range.

Test-Taking Strategy: Note the subject of the question, the level that should be reported. This indicates that you are looking for an abnormal level. Remember, the normal serum potassium level in the adult is 3.5 to 5.0 mEq/L. This will direct you to the correct option.

Option 1, 2, 4, 6 is correct answer.

Rationale: The normal values include the following: calcium, 8.6 to 10 mg/dL; magnesium, 1.6 to 2.6 mg/dL; phosphorus, 2.7 to 4.5 mg/dL; neutrophils, 1800 to 7800 cells/mm3; serum creatinine, 0.6 to 1.3 mg/dL; and white blood cells, 4500 to 11,000 cells/mm3. The calcium level noted is low; the magnesium level noted is low; the phosphorus level noted is normal; the neutrophil level noted is low; the serum creatinine level noted is normal; and the white blood cell level is low.

Test-Taking Strategy: Focus on the subject, the abnormal laboratory values. Recalling the normal laboratory values for the blood studies identified in the options will assist in answering this question.

Option 3 is correct answer.

Rationale: The normal range for total serum protein level in the adult client is 6 to 8 g/dL. The client with cirrhosis often has low total protein levels as a result of inadequate nutrition. Excess protein is not helpful, though, because a function of the liver is to metabolize protein. A diseased liver may not metabolize protein well. The options of 0.4 g/dL and 3.7 g/dL identify low values, and 9.8 g/dL identifies a high protein value.

Test-Taking Strategy: Note the strategic word most. Recalling the normal total protein level will direct you to the correct option.

Option 4 is correct answer.

Rationale: In the test result for glycosylated hemoglobin A1c, 7% or less indicates good control, 7% to 8% indicates fair control, and 8% or higher indicates poor control. This test measures the amount of glucose that has become permanently bound to the red blood cells from circulating glucose. Elevations in the blood glucose level will cause elevations in the amount of glycosylation. Thus the test is useful in identifying clients who have periods of hyperglycemia that are undetected in other ways. Elevations indicate continued need for teaching related to the prevention of hyperglycemic episodes.

Test-Taking Strategy: Focus on the subject, a glycosylated hemoglobin A1c level of 9%. Recalling the normal value and that an elevated value indicates hyperglycemia will assist in directing you to the correct option.

Option 1 is correct answer.

Rationale: The normal white blood cell count ranges from 4500 to 11,000/mm3. The client who has a decrease in the number of circulating white blood cells is immunosuppressed. The nurse implements neutropenic precautions when the client’s values fall sufficiently below the normal level. The specific value for implementing neutropenic precautions usually is determined by agency policy. The remaining options are normal values.

Test-Taking Strategy: Focus on the subject, the need to implement neutropenic precautions. Recalling that the normal white blood cell count is 4500 to 11,000 cells/mm3 will direct you to the correct option.

Option 4 is correct answer.

Rationale: The next action is to draw a sample for PT and INR level to determine the client’s anticoagulation status and risk for bleeding. These results will provide information as to how to best treat this client (e.g., if an antidote such as vitamin K or a blood transfusion is needed). The aPTT monitors the effects of heparin therapy.

Test-Taking Strategy: Focus on the subject, a client who has taken an excessive dose of warfarin. Eliminate the option with aPTT first because it is unrelated to warfarin therapy and relates to heparin therapy. Next, eliminate the options indicating to administer an antidote and to transfuse the client because these therapies would not be implemented unless the PT and INR levels were known.

Option 3 is correct answer.

Rationale: The normal serum amylase level is 25 to 151 units/L. With chronic cases of pancreatitis, the rise in serum amylase levels usually does not exceed three times the normal value. In acute pancreatitis, the value may exceed five times the normal value. The options of 45 units/L and 100 units/L are within normal limits. The option of 500 units/L is an extremely elevated level seen in acute pancreatitis.

Test-Taking Strategy: Focus on the subject, a client with chronic pancreatitis. Recalling the normal amylase level will direct you to the correct option.

Option 3 is correct answer.

Rationale: The normal hemoglobin level for an adult female client is 12 to 15 g/dL. Iron deficiency anemia can result in lower hemoglobin levels. Dehydration may increase the hemoglobin level by hemoconcentration. Heart failure and chronic obstructive pulmonary disease may increase the hemoglobin level as a result of the body’s need for more oxygen-carrying capacity.

Test-Taking Strategy: Note the strategic words most likely. Evaluate each of the options in terms of whether each is likely to raise or lower the hemoglobin level. Also, note the relationship between hemoglobin level in the question and the correct option.

Option 4 is correct answer.

Rationale: A normal platelet count ranges from 150,000 to 400,000 cells/mm3. The nurse should place the report containing the normal laboratory value in the client’s medical record. A platelet count of 300,000 cells/mm3 is not an elevated count. The count also is not low; therefore bleeding precautions are not needed.