Chapter 8 Laboratory Values and Diagnostics Copyright © 2016 by Elsevier, Inc. All rights reserved.

Laboratory Findings in Older Adults The older a person is, the more difficult is the interpretation of findings Special diligence is needed to interpret the results within the context of the person’s overall health and normal changes of aging While there are no differences in what is a normal result in a laboratory finding in an older adult compared to a younger adult, deviations are more likely to occur and put the person at greater risk of poor outcome (Box 8-1) Copyright © 2016 by Elsevier, Inc. All rights reserved. 2

Hematological Testing Associated with blood, lymph, and their component parts A number of disorders in older adults can be diagnosed or monitored with hematological testing (anemia, fatigue) Results can be affected by dehydration, inadequate nutrition, infection, and inflammation Copyright © 2016 by Elsevier, Inc. All rights reserved. 3

Hematological Testing (Cont.) Values: Red Blood Count (RBC) ◦Normal value: million/mm 3 Hemoglobin (Hb) ◦Normal value: g/dL Hematocrit (HcT) ◦Normal value: 39-48% Caution when interpreting H&H (Box 8-2) Copyright © 2016 by Elsevier, Inc. All rights reserved. 4

Hematological Testing (Cont.) Iron ◦ Serum concentration of iron is determined by a combination of its absorption, storage, and the breakdown and synthesis of Hb ◦ Iron studies  Serum iron  Ferritin  Total iron binding capacity  Transferrin Copyright © 2016 by Elsevier, Inc. All rights reserved. 5

Hematological Testing (Cont.) While anemia is not normal in the older adult, it is a common finding in frail older adults and those with chronic disease 10% of adults over 65 years have some type of anemia Diagnostic workup includes complete blood count (CBC) with differential, iron studies, folic acid, and B 12 Based on the World Health Organization definition of anemia, the group most likely to be anemic is black men Types of anemia (Box 8-4) Copyright © 2016 by Elsevier, Inc. All rights reserved. 6

Hematological Testing White Blood Cells Normal Value: ,000/mm 3 Granulocytes ◦ Neutrophils  Normal value: 55-70% ◦ Eosinophils  Normal value: 1-4% ◦ Basophils  Normal value: 0.5-1% Agranulocytes ◦ Monocytes  Normal value: 2-8% ◦ Lymphocytes  Normal value: 20-40% 7 Copyright © 2016 by Elsevier, Inc. All rights reserved.

Functions of White Blood Cells Neutrophils: stimulated by pyogenic infections, to fight bacteria Eosinophils: stimulated by allergic responses, to fight antigens and parasites Basophils: stimulated by the presence of allergens, transport histamine Lymphocytes: stimulated by the presence of viral infections. Divided into two types: T cells and B cells Monocytes: largest of the leukocytes, become macrophages when matured, which defend the body against foreign substances Copyright © 2016 by Elsevier, Inc. All rights reserved. 8

Hematological Testing Platelets ◦ Normal value: 150, ,000/mm 3 Important in the control of bleeding Platelet count does not change with aging; however, an increase in coagulation enzymes can lead to hypercoagulability in the older adult Platelet function is affected by nonsteroidal antiinflammatory drug (NSAID) products to include aspirin Copyright © 2016 by Elsevier, Inc. All rights reserved. 9

Measures of Inflammation ◦ Erythrocyte Sedimentation Rate  Indicator of inflammation, infection, necrosis, infarction, or advanced neoplasm  May be slightly elevated in older adults secondary to chronic disease ◦ C-Reactive Protein (CRP)  Produced during the acute phase of inflammation  Useful indicator for cardiac events and the course of other diseases Copyright © 2016 by Elsevier, Inc. All rights reserved. 10

Vitamins B Vitamins ◦ Folic acid: important for normal function of red blood cells (RBCs) and white blood cells ◦ B 12 : normal development of RBCs, neurological function, and DNA synthesis (Box 8-5) Vitamin D ◦ Deficiencies reduce the absorption of calcium into bone Copyright © 2016 by Elsevier, Inc. All rights reserved. 11

Blood Chemistry Studies Electrolytes ◦ Maintain a balance between intracellular and extracellular environment ◦ Regulate hydration, blood pH, and are critical for nerve and muscle function ◦ Most common  Sodium and chloride  Potassium  Glucose Copyright © 2016 by Elsevier, Inc. All rights reserved. 12

Disturbance in Sodium Levels Hyponatremia <130Hypernatremia >145 High prevalence in LTC facilities 3 categories: ◦ Decreased extracellular fluid (ECF) (diarrhea, renal salt losing) ◦ Increased ECF (heart failure) ◦ Normal ECF (SIADH, or syndrome of inappropriate antidiuretic hormone secretion) Most often caused by free water loss (vomiting, diarrhea, dehydration) Associated with mortality rate of 42% in LTC Associated with lethargy, irritability, weakness Copyright © 2016 by Elsevier, Inc. All rights reserved. 13

Disturbance in Potassium Levels Hypokalemia ◦ Muscle weakness ◦ Cramping ◦ Confusion ◦ Fatigue ◦ Paralytic Ileus ◦ Atrial and ventricular ectopy ◦ Tachycardia ◦ Fibrillation ◦ Sudden death Associated with: ◦ ECG changes  QT interval prolonged  T wave flattened or depressed  ST segment depressed Copyright © 2016 by Elsevier, Inc. All rights reserved. 14

Disturbance in Potassium Levels (Cont.) Hyperkalemia (Box 8-6) ◦ Impaired muscle activity ◦ Weakness ◦ Muscle pain/cramps ◦ Increased gastrointestinal motility ◦ Bradycardia ◦ Cardiac arrest Associated with: ◦ EKG changes  P wave flattened  T wave large, peaked  QRS broad  Biphasic QRS-T complex Copyright © 2016 by Elsevier, Inc. All rights reserved. 15

Glycosylated Hb Provides a snapshot of blood glucose over the last 120 days In nondiabetics should be 4-5.9% In diabetics: ◦ Less than 7% indicates good diabetic control ◦ 8-9% fair control ◦ Greater than 9% poor control Copyright © 2016 by Elsevier, Inc. All rights reserved. 16

Other Blood Chemistry Studies Uric Acid ◦End product of purine metabolism ◦Most often used in the diagnosis and treatment of gout ◦Important in the evaluation of renal failure and leukemia Prostate-Specific Antigen ◦Primary screening tool for prostate cancer ◦May be elevated in other conditions, questioning the use as a screening tool Copyright © 2016 by Elsevier, Inc. All rights reserved. 17

Laboratory Testing: Cardiac Health Acute Cardiac Events ◦ Creatine kinase ◦ Troponin I & T (gold standard) Testing and Monitoring Risk and Health ◦ Homocysteine ◦ B-type natriuretic peptide ◦ Lipid panel  Cholesterol  Triglycerides 18 Copyright © 2016 by Elsevier, Inc. All rights reserved.

Laboratory Testing: Body Proteins Serum Albumin ◦ Most often used to measure nutritional status ◦ Measures the half-life, which is representative of about 3 weeks ◦ Most useful as indicator of severity of illness and risk of mortality Prealbumin ◦ May be more informative of current nutritional status as the half-life is 2-3 days Copyright © 2016 by Elsevier, Inc. All rights reserved. 19

Laboratory Testing: Renal Health Blood Urea Nitrogen ◦ Measurement of nitrogen portion of urea; used as gross measurement for renal functioning ◦ Normal mg/dL Creatinine ◦ Key component in determining glomerular filtration rate (GFR) ◦ Used to diagnose and monitor renal function ◦ More accurate reflection of renal health than blood urea nitrogen (BUN) Copyright © 2016 by Elsevier, Inc. All rights reserved. 20

Therapeutic Blood Level Monitoring Anticoagulants ◦ Prothrombin time ◦ Partial thromboplastin time ◦ International normalized ratio (Table 8-4) Results are important for prompt adjustment of an individual’s dosage for anticoagulants Copyright © 2016 by Elsevier, Inc. All rights reserved. 21

Therapeutic Blood Level Monitoring (Cont.) Cardiac Rate Control ◦ Digoxin level  Blood level is general guide; must be combined with clinical presentation (including heart rate) of person  Observe for signs of toxicity Copyright © 2016 by Elsevier, Inc. All rights reserved. 22

Therapeutic Blood Level Monitoring (Cont.) Thyroid Panels ◦Includes thyroid stimulating hormone, Free T3 (Triidothyronine), and Free T4 (Thyroxin) ◦Used to diagnose or monitor thyroid disorders and their treatment ◦If goiter is present a thyroid scan with technetium may be necessary Copyright © 2016 by Elsevier, Inc. All rights reserved. 23

Urine Studies Urinalysis ◦ Specific gravity ◦ pH ◦ Protein ◦ Glucose ◦ Ketones ◦ Blood ◦ Bilirubin ◦ Nitrates ◦ Leukocytes ◦ Abnormalities frequently found in older adults because of high rates of diabetes, renal insufficiency, and subclinical bacteriuria and proteinuria ◦ Presence of bacteria and proteinuria requires further evaluation Copyright © 2016 by Elsevier, Inc. All rights reserved. 24

Healthy Aging: Implications for Gerontological Nursing Collecting and monitoring laboratory values are important nursing responsibilities Laboratory values are helpful tools in understanding clinical signs and symptoms Abnormal laboratory results trigger comprehensive patient assessments, obtaining information about clinical signs and symptoms, patient history, and psychosocial and physical examination Copyright © 2016 by Elsevier, Inc. All rights reserved. 25

Question 1 Most laboratory findings and their meanings are the same for: a. men and women. b. older adults and younger adults. c. younger adults of the same age. d. family members. Copyright © 2016 by Elsevier, Inc. All rights reserved. 26

Question 2 An indicator of cardiac events and inflammation is: a. CRP. b. serum iron. c. thyroxin. d. folic acid. Copyright © 2016 by Elsevier, Inc. All rights reserved. 27