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266 BASIC SKILLS IN INTERPRETING LABORATORY DATA
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QUICKVIEW | Chloride
PARAMETER DESCRIPTION COMMENTS
Common reference ranges
Adults and children 95–103 mEq/L (95–103 mmol/L)
Critical value Depends on underlying disorder
Natural substance? Yes
Inherent activity? Yes Primary anion in extracellular uid
and gastric juice, cardiac function,
acid–base balance
Location
Storage Extracellular uid Most abundant extracellular anion
Secretion/excretion Passively follows sodium and water Also inuenced by acid–base
balance
Major causes of…
High results
Associated signs and symptoms Associated with underlying disorder
Low results Nasogastric suction
Associated signs and symptoms Associated with underlying disorder
After insult, time to…
Initial elevation or positive result Hours to years, depending on
Peak values Hours to years, depending on
Normalization Days, if renal function is normal Faster with appropriate treatment
Drugs often monitored with test Loop diuretics, chloride- containing IV
Dehydration
Acidemia
Vomiting
Serum dilution
Alkalemia
chronicity
chronicity
uids (eg, saline solution), parenteral
nutrition, drugs that cause diarrhea
The faster the change, the more
dangerous the consequences
of underlying disorder
Causes of spurious results Bromides; iodides (falsely elevated)
CHAPTER 11 • ElECTRolyTEs, oTHER MinERAls, And TRACE ElEMEnTs 267
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QUICKVIEW | Magnesium
PARAMETER DESCRIPTION COMMENTS
Common reference ranges
Adults and children 1.7–2.4 mg/dL (0.7–1 mmol/L)
1.4–2 mEq/L
Critical value >5 or <1 mEq/L (>2.5 or <0.5
mmol/L)
Natural substance? Yes
Inherent activity? Yes Enzyme cofactor, thermoregulation,
Location
Storage 50% bone, 45% intracellular uid,
5% extracellular uid
Secretion/excretion Filtration by kidneys 3%–5% reabsorbed
Major causes of…
High results
Associated signs and symptoms Neuromuscular manifestations Table
Low results Excessive loss from GI tract or kidneys Alcoholism and diuretics
Associated signs and symptoms Neuromuscular and cardiovascular
Renal failure Usually in presence of increased
Decreased intake
manifestations, including weakness,
muscle fasciculation, tremor,
tetany, increased reexes, and EKG
abnormalities
Acute changes more dangerous
than chronic abnormalities
muscle contraction, nerve
conduction, calcium and potassium
homeostasis
intake
11-9
More severe with acute changes
After insult, time to…
Initial elevation or positive result Hours to years, depending on
Peak values Hours to years, depending on
Normalization Days, if renal function is normal Faster with appropriate treatment
Drugs often monitored with test Diuretics, proton pump inhibitors
Causes of spurious results Hemolyzed samples (falsely elevated)
chronicity
chronicity
The faster the change, the more
dangerous the consequences
268 BASIC SKILLS IN INTERPRETING LABORATORY DATA
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QUICKVIEW | Calcium
PARAMETER DESCRIPTION COMMENTS
Common reference ranges
Adults Total calcium:
9.2–11 mg/dL (2.3–2.8 mmol/L)
Ionized calcium:
4–4.8 mg/dL (1–1.2 mmol/L)
Children Total calcium:
8–10.5 mg/dL (2–2.6 mmol/L)
Ionized calcium:
1.16–1.45 mmol/L
Critical value >14 or <7 mg/dL (>3.5 or <1.8 mmol/L) Also depends on serum albumin and
Natural substance? Yes
Inherent activity? Yes Preservation of cellular membranes,
Location
Storage 99.5% in bone and teeth Very closely regulated
Secretion/excretion Filtration by kidneys Small amounts excreted into GI
Major causes of…
High results Malignancy Also thiazide diuretics, lithium,
Hyperparathyroidism More severe with acute onset
Associated signs and
symptoms
Low results Vitamin D deciency
Associated signs and
symptoms
After insult, time to…
Initial elevation or positive
result
Peak values Hours to years, depending on chronicity
Normalization Days, if renal function is normal Faster with appropriate treatment
Drugs often monitored
with test
Causes of spurious results Hypoalbuminemia Ionized calcium concentration
Vague GI complaints neurologic and
cardiovascular symptoms, and renal dysfunction
CKD
Hypoparathyroidism
Hyperphosphatemia
Acute pancreatitis
Loop diuretics
Calcitonin
Zoledronic acid
Denosumab
Primarily neuromuscular (eg, fatigue,
depression, memory loss, hallucinations,
seizures, tetany)
Hours to years, depending on chronicity The faster the change, the more
Loop diuretics, calcitonin, vitamin D, calcium
supplements, phosphate binders
Approximately half of calcium in the
blood is bound to serum proteins;
only ionized (free) calcium is
physiologically active
Please refer to Chapter 23 for age-
specic ranges for children
pH values
propagation of neuromuscular
activity, regulation of endocrine
functions, blood coagulation, bone
metabolism, phosphate homeostasis
tract from saliva, bile, and pancreatic
and intestinal secretions
vitamin D, teriparatide, and calcium
supplements
Hypocalcemia due to
hypoalbuminemia is asymptomatic
(ionized calcium concentration
unaffected)
More severe with acute onset
dangerous the consequences
usually unaffected
CHAPTER 11 • ElECTRolyTEs, oTHER MinERAls, And TRACE ElEMEnTs 269
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QUICKVIEW | Phosphorus
PARAMETER DESCRIPTION COMMENTS
Common reference ranges
Adults 2.3–4.7 mg/dL (0.74–1.52 mmol/L)
Children 4–7.1 mg/dL (1.3–2.3 mmol/L) See Chapter
normal ranges based on patient’s age
Critical value >8 or <1 mg/dL (>2.6 or
<0.3 mmol/L)
Natural substance? Yes Most abundant intracellular anion
Inherent activity? Yes Bone and tooth integrity, cellular
Location
Storage Extracellular uid, cell membrane
structure, intracellular uid, collagen,
bone
Secretion/excretion Filtration by kidneys Mostly reabsorbed
Major causes of…
High results
Decreased renal excretion Renal failure is the most common cause
Extracellular shifting Rhabdomyolysis; tumor lysis syndrome
Increased intake of phosphate or
vitamin D
Acute changes more dangerous than
chronic abnormalities
membrane integrity, phospholipid
synthesis, acid–base balance, calcium
homeostasis, enzyme activation,
formation of high- energy bonds
85% in bone
23 for detailed listing of
Associated signs and symptoms Due primarily to hypocalcemia and
hyperparathyroidism
Low results Increased renal excretion Also can occur in renal failure
Intracellular shifting Insulin use
Decreased intake of phosphate or
vitamin D
Associated signs and symptoms Bone pain, weakness, malaise,
hypocalcemia, cardiac failure,
respiratory failure
After insult, time to…
Initial elevation or positive result Usually over months to years
Peak values Usually over months to years
Normalization Over days with renal transplantation
Drugs often monitored with test Vitamin D, phosphate binders
Causes of spurious results Hemolyzed samples (falsely elevated)
and methotrexate (falsely elevated)
2,3-DPG = 2,3- diphosphoglycerate.
See Quickview for calcium
(hypocalcemia)
Usually due to diminished intracellular
ATP and erythrocyte 2,3-DPG
concentrations
270 BASIC SKILLS IN INTERPRETING LABORATORY DATA
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QUICKVIEW | Copper
PARAMETER DESCRIPTION COMMENTS
Common reference ranges
Adults 70–140 mcg/dL (11–22 µmol/L) (men);
80–155 mcg/dL (13–24 µmol/L) (women)
Children 20–70 mcg/dL (3.1–11 µmol/L) 0–6 mo
90–190 mcg/dL (14.1–29.8 µmol/L) 6 yr
80–160 mcg/dL (12.6–25.1 µmol/L) 12 yr
Critical value Not applicable
Natural substance? Yes
Inherent activity? Yes Companion to iron enzyme cofactor,
Hgb synthesis, collagen and elastin
synthesis, metabolism of many
neurotransmitters, energy generation,
regulation of plasma lipid levels, cell
protection against oxidative damage
Location
Storage One- third in liver and brain; one- third
in muscles; one-third in heart, spleen,
kidneys, and blood (erythrocytes and
neutrophils)
Secretion/excretion Mainly by biliary excretion; only
0.5%–3% of daily intake found in urine
Major causes of…
High results
Associated signs and
symptoms
Low results Infants with chronic diarrhea
Associated signs and
symptoms
Deliberate ingestion of large amounts
(>15 mg of elemental copper); Wilson
disease
Nausea, vomiting, intestinal cramps,
diarrhea
Malabsorption syndromes Following bariatric surgery
Decreased intake over months
Menkes syndrome
Neutropenia, iron- deciency
anemia, abnormal glucose tolerance,
arrhythmias, hypercholesterolemia,
atherosclerosis, depressed immune
function, defective connective tissue
formation, demineralization of bones
95% of circulating copper is protein
bound as ceruloplasmin
Uncommon in humans
Larger ingestions lead to shock, hepatic
necrosis, intravascular hemolysis, renal
impairment, coma, and death
Can affect any system or organ whose
enzymes require copper for proper
functioning
Drugs often monitored with
test
Copper supplements, possibly during
chronic parenteral nutrition
Serum copper concentrations not
routinely monitored
CHAPTER 11 • ElECTRolyTEs, oTHER MinERAls, And TRACE ElEMEnTs 271
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QUICKVIEW | Zinc
PARAMETER DESCRIPTION COMMENTS
Common reference ranges
Adults and children 50–150 mcg/dL (7.7–23 µmol/L) Increased risk for developing
symptomatic zinc deciency
Critical value <50 mcg/dL (<7.7 µmol/L)
Natural substance? Yes
Inherent activity? Yes Enzyme constituent and cofactor;
carbohydrate, protein, lipid, and nucleic
acid metabolism; tissue growth; tissue
repair; cell membrane stabilization;
bone collagenase activity and collagen
turnover; immune response; food
intake control; spermatogenesis and
gonadal maturation; normal testicular
function
Location
Storage Liver, pancreas, spleen, lungs, eyes
(retina, iris, cornea, lens), prostate,
skeletal muscle, bone, erythrocytes,
neutrophils
Secretion/excretion Primarily in pancreatic and intestinal
secretions; also lost dermally through
sweat, hair and nail growth, and skin
shedding
Major causes of…
High results
Associated signs and
symptoms
Low results Low intake (infants) Rare from inadequate dietary intake in
Large intake Uncommon in humans
Drowsiness, lethargy, nausea, vomiting,
diarrhea, increases in serum lipase and
amylase concentrations
Decreased absorption (acrodermatitis
enteropathica)
Increased used (rapidly growing
adolescents and menstruating, lactating,
or pregnant women)
60%–62% in skeletal muscle,
20%–28% in bone, 2%–4% in liver
Except in certain disease states, only
2% lost in urine
adults
Associated signs and
symptoms
Drugs often monitored with
test
Causes of spurious results Hemolyzed samples; 24- hr intrapatient
Increased loss (hyperzincuria)
Manifests in numerous organs and
physiologic systems
Zinc supplements, possibly during
chronic parenteral nutrition
variability
Table 11-13
Serum zinc concentrations not
routinely monitored
High zinc content in erythrocytes and
neutrophils
272 BASIC SKILLS IN INTERPRETING LABORATORY DATA
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QUICKVIEW | Manganese
PARAMETER DESCRIPTION COMMENTS
Common reference ranges
Adults Varies depending on array method,
whether sample is blood or serum,
and patient age; typical whole blood
manganese concentrations range from
4–15 mcg/L, or 72–270 nmol/L.
Children 2–3 mcg/L (36–55 nmol/L)
2.4–9.6 mcg/L (44–175 nmol/L) Newborn
0.8–2.1 mcg/L (15–38 nmol/L) 2–18 yr
Critical value Not applicable
Natural substance? Yes
Inherent activity? Yes Enzyme cofactor; carbohydrate, protein,
and lipid metabolism; protection of cells
from free radicals; steroid biosynthesis;
metabolism of biogenic amines; normal
brain function
Magnesium may substitute for
manganese in most instances
Location
Storage Bone, liver, pancreas, pituitary gland Circulating manganese loosely bound to
transmanganin
Secretion/excretion Primarily in biliary and pancreatic
secretions; limited excretion in urine
Major causes of…
High results
Associated signs and
symptoms
Low results After several weeks to months of omission
Associated signs and
symptoms
Long- term parenteral nutrition with daily
multitrace elements; accidental exposure
to manganese compounds, such as in
manganese mines
Encephalopathy and profound neurologic
disturbances mimicking Parkinson disease
from diet or parenteral nutrition
Weight loss, slow hair and nail growth,
hair color change, transient dermatitis,
hypocholesterolemia, hypotriglyceridemia
Other GI routes also may be used in
manganese overload
One of least toxic trace elements
Accumulates in liver and brain
Rare from inadequate dietary intake
Seen mostly in experimental subjects
Drugs often monitored
with test
Manganese supplements, possibly during
chronic parenteral nutrition
CHAPTER 11 • ElECTRolyTEs, oTHER MinERAls, And TRACE ElEMEnTs 273
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QUICKVIEW | Chromium
PARAMETER DESCRIPTION COMMENTS
Common reference ranges
Adults 0.3–0.9 ng/mL, serum
0.7–28 ng/mL, whole blood
Children Unknown Analysis of chromium in biological
Critical value Unknown
Natural substance? Yes
Inherent activity? Yes Cofactor for insulin and metabolism of
Location
Storage Hair, kidneys, skeleton, liver, spleen,
lungs, testes, large intestines
Secretion/excretion Excretion in urine Circulating insulin may affect excretion
Major causes of…
Low results
Associated signs and
symptoms
Decreased intake
Glucose intolerance; hyperinsulinemia;
hypercholesterolemia; possibly,
increased risk of cardiovascular disease
Analysis of chromium in biological
uids and tissues is difcult
uids and tissues is difcult
glucose, cholesterol, and triglycerides
Chromium circulates as free Cr3+,
bound to transferrin and other
proteins, and as an organic complex
Mainly due to its role as insulin
cofactor
Drugs often monitored with
test
Chromium supplement, possibly during
chronic parenteral nutrition
Serum chromium concentration not
routinely monitored
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Interpretation of Laboratory Tests
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Associated with the Assessment of
12
OBJECTIVES
After completing this chapter, the
reader should be able to
•
Describe the current dening criteria
and parameters for the diagnosis of
malnutrition
•
Discuss the relevance and feasibility
of laboratory tests that have been/
are currently used in the assessment
of a patient’s nutritional status
based on the current denition of
malnutrition
•
Determine whether specic
laboratory tests in a patient’s prole
provide valid and specic information
regarding the patient’s nutritional
status
•
Propose a patient- specic
assessment plan for monitoring a
patient’s nutritional status
DOI 10.37573/9781585286423.012
Nutritional Status
Lingtak-Neander Chan and Sharon Wu
Identifying patients who are at risk for malnutrition and continually monitoring a
patient’s nutritional status are critical components of the comprehensive patient care
plan. Research has conrmed that the presence of malnutrition consistently correlates
with increased length of stay in the hospital and the intensive care unit (ICU), prolonged mechanical ventilation, increased risk for healthcare- associated infections and
complications, delayed recovery from surgery, delayed wound healing, and increased
mortality.
and increases healthcare costs.8 Implementation of optimal nutrition support therapy
in a timely manner has been shown to improve patient outcomes and reduce costs
to the healthcare system.9 e Joint Commission has established standards related to
nutritional screening and assessment that are applicable to patients in all acute care
and long- term care facilities.
performed by pharmacists. A patient’s malnutrition risk and clinical conditions determine the needs and urgency for specialized nutrition support, such as enteral and
parenteral nutrition. Use of specialized nutrition support has implications on patient
safety, such as optimization of uid and electrolyte balance, determining route and
method of drug administration, and addressing drug compatibility concerns. Additionally, patients with malnutrition are at increased risk for falls and frailty. Altered
body composition such as sarcopenia, dehydration, edema, and end organ dysfunction may alter pharmacokinetic and pharmacodynamic response to pharmacotherapy.
erefore, identifying malnourished patients or those who are at risk for malnutrition may help pharmacists adjust and optimize pharmacotherapeutic approaches and
decisions that can improve patient safety and outcomes.
torically, the term malnutrition is mostly associated with starvation and famine leading to kwashiorkor and marasmus. Kwashiorkor, sometimes known as edematous
malnutrition, is a form of protein- calorie malnutrition most commonly associated
with hunger and starvation. Patients typically present with loss of muscle and generalized edema and a large, protuberant belly. Marasmus is also a form of protein- calorie
malnutrition. It generally presents with overall weight loss with severe muscle mass
depletion without edema. e two conditions are not mutually exclusive because
marasmus may progress to kwashiorkor in some patients. With changes in the global
economy and landscape and improvements in agriculture, healthcare, education, living standards, and high- risk medical/surgical interventions, the presentation of malnutrition has expanded. e presentation of malnutrition in modern days may not be
limited to a lack of access to food in general. Instead, malnutrition more commonly
presents as nutrient imbalance, undernutrition, micronutrient abnormalities, obesity,
cachexia, frailty, and sarcopenia.11 In particular, sarcopenia, or loss of muscle mass,
is the current malnutrition- related research focus. Its prevalence is especially high
among older adults, hospitalized patients, critically ill patients, and patients with
cancer (Table12-1).12 e evolving changes also challenge the existing clinical denition of malnutrition. According to the tenth revision of International Classication
of Diseases (ICD) codes, the clinical features that t the diagnosis of malnutrition are
still limited (Table12-2) and do not fully address the current understanding of the
etiology and presentation of malnutrition.
1-7
Malnutrition is also associated with increased use of healthcare resources
10
Understanding a patient’s nutritional status has a direct implication on the roles
e perception and understanding of malnutrition have evolved over time. His-
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