Ketones, Blood and Urine


Ketones, Blood and Urine

Synonym/acronym: Ketone bodies, acetoacetate, acetone.

Common use

To investigate diabetes as the cause of ketoacidosis and monitor therapeutic interventions.

Specimen

Serum (1 mL) collected from gold-, red-, or red/gray-top tube. Urine (5 mL), random or timed specimen, collected in a clean plastic collection container.

Normal findings

(Method: Colorimetric nitroprusside reaction) Negative.

Description

Ketone bodies refer to the three intermediate products of metabolism: acetone, acetoacetic acid, and β-hydroxybutyrate. Even though β-hydroxybutyrate is not a ketone, it is usually listed with the ketone bodies. In healthy individuals, ketones are produced and completely metabolized by the liver so that measurable amounts are not normally present in serum. Ketones appear in the urine before a significant serum level is detectable. If the patient has excessive fat metabolism, ketones are found in blood and urine. Excessive fat metabolism may occur if the patient has impaired ability to metabolize carbohydrates, inadequate carbohydrate intake, inadequate insulin levels, excessive carbohydrate loss, or increased carbohydrate demand. A strongly positive acetone result without severe acidosis, accompanied by normal glucose, electrolyte, and bicarbonate levels, is strongly suggestive of isopropyl alcohol poisoning. A low-carbohydrate or high-fat diet may cause a positive acetone test. Ketosis in people with diabetes is usually accompanied by increased glucose and decreased bicarbonate and pH. Extremely elevated levels of ketone bodies can result in coma. This situation is particularly life threatening in children younger than 10 yr.

This procedure is contraindicated for

    N/A

Indications

  • Assist in the diagnosis of starvation, stress, alcoholism, suspected isopropyl alcohol ingestion, glycogen storage disease, and other metabolic disorders
  • Detect and monitor treatment of diabetic ketoacidosis
  • Monitor the control of diabetes
  • Screen for ketonuria due to acute illness or stress in nondiabetic patients
  • Screen for ketonuria to assist in the assessment of inborn errors of metabolism
  • Screen for ketonuria to assist in the diagnosis of suspected isopropyl alcohol poisoning

Potential diagnosis

Increased in

  • Ketones are generated in conditions that involve the metabolism of carbohydrates, fatty acids, and protein.

  • Acidosis
  • Branched-chain ketonuria
  • Carbohydrate deficiency
  • Eclampsia
  • Fasting or starvation
  • Gestational diabetes
  • Glycogen storage diseases
  • High-fat or high-protein diet
  • Hyperglycemia
  • Ketoacidosis of alcoholism and diabetes
  • Illnesses with marked vomiting and diarrhea
  • Isopropyl alcohol ingestion
  • Methylmalonic aciduria
  • Postanesthesia period
  • Propionyl coenzyme A carboxylase deficiency

Decreased in

    N/A

Critical findings

  • Strongly positive test results for glucose and ketones

  • Note and immediately report to the health-care provider (HCP) any critically increased or decreased values and related symptoms.

  • It is essential that a critical finding be communicated immediately to the requesting health-care provider (HCP). A listing of these findings varies among facilities.

  • Timely notification of a critical finding for lab or diagnostic studies is a role expectation of the professional nurse. Notification processes will vary among facilities. Upon receipt of the critical value the information should be read back to the caller to verify accuracy. Most policies require immediate notification of the primary HCP, Hospitalist, or on-call HCP. Reported information includes the patient’s name, unique identifiers, critical value, name of the person giving the report, and name of the person receiving the report. Documentation of notification should be made in the medical record with the name of the HCP notified, time and date of notification, and any orders received. Any delay in a timely report of a critical finding may require completion of a notification form with review by Risk Management.

  • Note and immediately report to the health-care provider (HCP) strongly positive results in urine and related symptoms. An elevated level of ketone bodies is evidenced by fruity-smelling breath, acidosis, ketonuria, and decreased level of consciousness. Administration of insulin and frequent blood glucose measurement may be indicated.

Interfering factors

  • Drugs that may cause an increase in serum ketone levels include acetylsalicylic acid (if therapy results in acidosis, especially in children), albuterol, fenfluramine, nifedipine, and rimiterol.
  • Drugs that may cause a decrease in serum ketone levels include acetylsalicylic acid and valproic acid. Increases have been shown in hyperthyroid patients receiving propranolol and propylthiouracil.
  • Drugs that may increase urine ketone levels include acetylsalicylic acid (if therapy results in acidosis, especially in children), ether, metformin, and niacin.
  • Drugs that may decrease urine ketone levels include acetylsalicylic acid.
  • Urine should be checked within 60 min of collection.
  • Bacterial contamination of urine can cause false-negative results.
  • Failure to keep reagent strip container tightly closed can cause false-negative results. Light and moisture affect the ability of the chemicals in the strip to perform as expected.
  • False-negative or weakly false-positive test results can be obtained when β-hydroxybutyrate is the predominating ketone body in cases of lactic acidosis.

Nursing Implications and Procedure

Pretest

  • Positively identify the patient using at least two unique identifiers before providing care, treatment, or services.
  • Patient Teaching: Inform the patient this test can assist in diagnosing metabolic disorders such as diabetes.
  • Obtain a history of the patient’s complaints, including a list of known allergens, especially allergies or sensitivities to latex.
  • Obtain a history of the patient’s endocrine system, symptoms, and results of previously performed laboratory tests and diagnostic and surgical procedures.
  • Obtain a list of the patient’s current medications, including herbs, nutritional supplements, and nutraceuticals (see Effects of Natural Products on Laboratory Values online at DavisPlus).
  • Review the procedure with the patient. Inform the patient that blood specimen collection takes approximately 5 to 10 min. The amount of time required to collect a urine specimen depends on the level of cooperation from the patient. Address concerns about pain and explain that there may be some discomfort during the venipuncture.
  • Sensitivity to social and cultural issues, as well as concern for modesty, is important in providing psychological support before, during, and after the procedure.
  • Note that there are no food, fluid, or medication restrictions, unless by medical direction.

Intratest

  • Potential complications: N/A
  • Observe standard precautions, and follow the general guidelines in Patient Preparation and Specimen Collection. Positively identify the patient, and label the appropriate specimen container with the corresponding patient demographics, initials of the person collecting the specimen, date, and time of collection. Perform a venipuncture as appropriate.

    • Blood

  • Avoid the use of equipment containing latex if the patient has a history of allergic reaction to latex.
  • Instruct the patient to cooperate fully and to follow directions. Direct the patient to breathe normally and to avoid unnecessary movement.
  • Positively identify the patient, and label the appropriate specimen container with the corresponding patient demographics, initials of the person collecting the specimen, date, and time of collection. Perform a venipuncture. Alternatively, a fingerstick or heel stick method of specimen collection can be used.
  • Remove the needle and apply direct pressure with dry gauze to stop bleeding. Observe/assess venipuncture site for bleeding or hematoma formation and secure gauze with adhesive bandage.

    • Urine

  • Review the procedure with the patient. Explain to the patient how to collect a second-voided midstream void, then drink a glass of water, wait 30 min, and then try to void again.
  • Instruct the patient to avoid excessive exercise and stress before specimen collection.

    • Clean-Catch Specimen

  • Instruct the male patient to (1) thoroughly wash his hands, (2) cleanse the meatus, (3) void a small amount into the toilet, and (4) void directly into the specimen container.
  • Instruct the female patient to (1) thoroughly wash her hands; (2) cleanse the labia from front to back; (3) while keeping the labia separated, void a small amount into the toilet; and (4) without interrupting the urine stream, void directly into the specimen container.

    • Blood or Urine

  • Promptly transport the specimen to the laboratory for processing and analysis.

Post-Test

  • Inform the patient that a report of the results will be made available to the requesting HCP, who will discuss the results with the patient.
  • Nutritional Considerations: Increased levels of ketone bodies may be associated with diabetes. There is no “diabetic diet”; however, many meal-planning approaches with nutritional goals are endorsed by the American Dietetic Association. Patients who adhere to dietary recommendations report a better general feeling of health, better weight management, greater control of glucose and lipid values, and improved use of insulin. Instruct the patient, as appropriate, in nutritional management of diabetes. The 2013 Guideline on Lifestyle Management to Reduce Cardiovascular Risk published by the American College of Cardiology (ACC) and the American Health Association (AHA) in conjunction with the National Heart, Lung, and Blood Institute (NHLBI) recommends a “Mediterranean”-style diet rather than a low-fat diet. The new guideline emphasizes inclusion of vegetables, whole grains, fruits, low-fat dairy, nuts, legumes, and nontropical vegetable oils (e.g., olive, canola, peanut, sunflower, flaxseed) along with fish and lean poultry. A similar dietary pattern known as the Dietary Approaches to Stop Hypertension (DASH) diet makes additional recommendations for the reduction of dietary sodium. Both dietary styles emphasize a reduction in consumption of red meats, which are high in saturated fats and cholesterol, and other foods containing sugar, saturated fats, trans fats, and sodium. If triglycerides also are elevated, the patient should be advised to eliminate or reduce alcohol. The nutritional needs of each diabetic patient need to be determined individually (especially during pregnancy) with the appropriate HCPs, particularly professionals trained in nutrition.
  • Impaired glucose tolerance may be associated with diabetes. Instruct the patient and caregiver to report signs and symptoms of hypoglycemia (weakness, confusion, diaphoresis, rapid pulse) or hyperglycemia (thirst, polyuria, hunger, lethargy).
  • Nutritional Considerations: Increased levels of ketone bodies may be associated with poor carbohydrate intake in an unbalanced diet; therefore, the body breaks down fat instead of carbohydrate for energy. Increasing carbohydrate intake in the patient’s diet reduces the levels of ketone bodies. Carbohydrates can be found in starches and sugars. Starch is a complex carbohydrate that can be found in foods such as grains (breads, cereals, pasta, rice) and starchy vegetables (corn, peas, potatoes). Sugar is a simple carbohydrate that can be found in natural foods (fruits and natural honey) and processed foods (desserts and candy).
  • Recognize anxiety related to test results, and be supportive of perceived loss of independence and fear of shortened life expectancy. Discuss the implications of abnormal test results on the patient’s lifestyle. Provide teaching and information regarding the clinical implications of the test results, as appropriate. Emphasize, if indicated, that good glycemic control delays the onset and slows the progression of diabetic retinopathy, nephropathy, and neuropathy. Educate the patient regarding access to counseling services, as appropriate. Provide contact information, if desired, for the American Diabetes Association (www.diabetes.org) or the American Heart Association (www.americanheart.org).
  • Reinforce information given by the patient’s HCP regarding further testing, treatment, or referral to another HCP. Answer any questions or address any concerns voiced by the patient or family.
  • Depending on the results of this procedure, additional testing may be performed to evaluate or monitor progression of the disease process and determine the need for a change in therapy. The ADA recommends A1C testing 4 times a year for insulin-dependent type 1 or type 2 diabetes and twice a year for non-insulin-dependent type 2 diabetes. The ADA also recommends that testing for diabetes commence at age 45 for asymptomatic individuals and continue every 3 yr in the absence of symptoms. Evaluate test results in relation to the patient’s symptoms and other tests performed.

Related Monographs

  • Related tests include ACTH, angiography adrenal, anion gap, blood gases, BUN, calcium, catecholamines, cholesterol (HDL, LDL, total), cortisol, C-peptide, DHEA, electrolytes, fecal analysis, fecal fat, fluorescein angiography, fructosamine, fundus photography, gastric emptying scan, GTT, glycated hemoglobin A1C, HVA, insulin, insulin antibodies, lactic acid, lipoprotein electrophoresis, metanephrines, microalbumin, osmolality, phosphorus, UA, and visual fields test.
  • Refer to the Endocrine System table at the end of the book for related tests by body system.