Lab Medicine (Part 2) Flashcards
1
Q
Lymphocytes reference values
A
- ~ 10 μm in diameter
- ~ 30% leukocytes
- T-lymphocytes: 75-80%
- B-lymphocytes: 10-15%
2
Q
Lymphocytes role
A
- Host response against viral infection: humoral immunity, cell mediated immunity
- Produce cytokines (lymphokines): interferon, interleukins
3
Q
B lymphocytes mechanism
A
- Possess antigen-specific receptors
- B cell binds to antigen
- Binds with matching receptor on T helper cell
- T cell releases cytokines
- Activation of B cell > plasma cell > antibody production
4
Q
T lymphocytes (60-80%)
A
- T4 helper cells (CD4)
- T8 cells (CD8)
5
Q
T4 helper cells (CD4)
A
- Require antigen Class II protein for activation
- Possess antigen specific receptors
6
Q
T8 cells (CD8)
A
- “true” suppressors CD8+ and CD11+
- Cytotoxic killers – CD8- and CD11-
7
Q
CD4 counts reference values
A
- Immunocompetent: 500 – 1500 cells/mm3
- “threshold” for management: < 500 cells/mm3
- Complications: <350 cells/mm3
8
Q
CD4 viral load
A
- Quantity of HIV-RNA in the plasm
9
Q
CD4 “ideal” reference values
A
- “ideal”: 4500-5000 copies/ml
- Initiation of therapy: 30,000 copies/ml
- “undetectable”: < 400 copies/ml
10
Q
Monocytes reference values
A
- ~4% total leukocytes
- 14 to 20 μm in diameter
11
Q
Monocyte role
A
- Become macrophage
- Activate T cells
- Produce leukotrienes (interleukin 1, tumor necrosis factor)
12
Q
Platelet reference values
A
- 150,000 – 400,000/μl
- Can be acute phase reactant
13
Q
Platelet aggregation test
A
- Measures rate platelets clump when in contact with known aggregator (e.g. ADP, ristocetin)
14
Q
Thrombocythemia
A
- Unregulated production with abnormal platelet function
15
Q
Platelet Function Assay – PFA-100
A
- Collect citrated specimen
- Flows through capillary tube through a membrane with an aperture
- Membrane saturated with platelet activators
16
Q
Membrane saturated with platelet activators in PFA
A
- Collagen/epinephrine
- Collagen/ADP
17
Q
In PFA, platelet function is determined by
A
- The time is takes to occlude the membrane
- Collagen/epinephrine (CEPI): 79-170 seconds
- Collagen/ADP (CADP): 55-112 seconds
- Also utilized to evaluate anti-aggregation effects of certain drugs
18
Q
Mean platelet volume
A
- Average volume of platelet
- Reference range 7.5-11.5
19
Q
Elevated mean platelet volume
A
- Increased risk of myocardial infarction
- Increased risk of stroke
- Thrombocytopenia with sepsis
- ITP
20
Q
Thrombocytopenia inflammatory disorders
A
- Infection
- Neoplasm
21
Q
Thrombocytopenia systemic disease
A
- Uremia
- Abnormal serum proteins
- Myeloproliferative disorders
22
Q
Thrombocytopenia drugs
A
- Aspirin and NSAID’s
- Alcohol inhibits ADP-related aggregation
23
Q
Thrombocytopenia < 20,000 RBC
A
- Spontaneous bleeding
24
Q
Thrombocytopenia etiologies
A
- ITP
- Viral, bacterial, rickettsial infection
- CHF, congenital heart disease
- HIV
- Alcohol toxicity
25
Heparin induced thrombocytopenia type 1
- 1 – 2 days after exposure
| - Transient
26
Heparin induced thrombocytopenia type 2
- 5-14 days after exposure
- Auto-immune
- Heparin-PF4 complex
- Decreased 50% platelet baseline
- Platelet disruption > clot formation
27
Plasma collection tubule
- Heparin tube
- Green/gray top
- Separates plasma from whole blood
- Inhibits action of thrombin
- Serum: does not posses clotting factors
- Plasma: contains clotting factor
28
Platelet rich plasma
- α-granule degranulation
- Macrophage signalling proteins
- Anti-microbial activity
- Minimum of 1,000,000 platelets/mL
- Activated by thrombin or calcium
29
α-granule degranulation
- PDGF
- TGF-β
- PF4
- IL-1
- VEGF
- Numerous other growth factors
30
PF4
- Immune system that is targeted for an autoimmune response
31
Liver function
- Intrahepatic
| - Extrahepatic
32
Intrahepatic function
- Catabolic = Ability to breakdown or metabolize substances
| - Anabolic = Ability to synthesize proteins
33
Extrahepatic function
- Biliary
- Ability to conjugate with bile acids
- Ability to excrete conjugated acids
34
Lactate dehydrogenase reference values
- Reference value: 38-62 U/L
| - Tetrameric molecule - ubiquitous
35
Lactate dehydrogenase in intrahepatic liver function
- LDH5 is almost exclusive to liver
- LDH1 and LDH2 are plentiful in heart and RBC’s
- LDH2 more prevalent than LDH1
36
Lactate dehydrogenase with MI
- With MI, a “flip” occurs
- LDH1/LDH2 ratio > 1.0
- Rises 24 to 48 hours after injury
- Peaks in 3 to 6 days
37
LDH highest elevations
- 4 to 40 fold
- Megaloblastic anemia
- Lymphomas
- Neoplastic conditions
38
LDH moderate elevations
- 2 to 4 fold
- Myocardial infarction
- Pulmonary infarction
- Leukemia
- Muscular dystrophy
39
LDH slight elevations
- ~ 2 fold
- Hepatitis
- Obstructive jaundice
40
LDH in congestive heart failure
- LDH1 and LDH5 may be elevated
- Elevation of brain natriuretic peptide is also highly consistent with CHF
- BNP levels elevate as the ventricular myocytes are stretched
- Levels correlate with disease severity
41
LDH in congestive heart failure reference values
- Normal < 50 pg/ml
- “Gray Area” 100 – 500 pg/ml
- Positive CHF > 500 pg.ml
42
Serum glutamate oxaloacetate transaminase (SGOT)and aspartate aminotransferase (AST)
- Reference values: 11-32 U/L
| - Primarily in mitochondria of liver and heart
43
SGOT and AST: mitochondria of liver and heart
- Transaminiation reaction between aspartate and alpha-ketoglutamic acid
- Amino acid catabolism
- Requires pyridoxine (Vitamin B6)
44
Hepatic SGOT/AST elevation
- Marked elevation: hepatitis, chronic liver disease
| - Moderate elevation: cirrhosis, AST:ALT ratio 2:1, alcoholic liver damage
45
Cardiac SGOT/AST elevation
- Elevates with MI
- Begins to rise at 12 hours
- Peaks at 36 hours
46
SGOT/ALT (alanine aminotransferase) reference values
- 3-30 U/L
- Catalyzes the amino group between alanine and alpha-ketoglutamic acid
In cytosol of hepatocytes
- Catalyzes the amino group between alanine and alpha-ketoglutamic acid
In cytosol of hepatocytes
47
SGOT/ALT highest elevations
- 20 fold or greater
- Viral hepatitis
- Toxic hepatitis
48
SGOT/ALT moderate elevations
- 3 – 10 fold elevation
- Mononucleosis
- Chronic active hepatitis
- Bile duct obstruction
49
SGOT/ALT mild elevations
- Inflammatory damage
50
Anabolic proteins (intrahepatic function)
- Vitamin K dependent clotting factors
| - Serum proteins (Albumin, Fibrinogen, Globulins, antibodies)
51
Hepatic alkaline phosphatase reference value
- 25-165 U/L
52
Hepatic alkaline phosphatase
- Most common measure for biliary obstruction
| - High levels present in cells that are metabolically active
53
Hepatic alkaline phosphatase two enzymes
- Hepatic – heat stabile
| - Bone – heat labile
54
Hepatic alkaline phosphatase high elevations
- 10 fold or greater
- Biliary cirrhosis
- Extrahepatic bile duct obstruction
55
Hepatic alkaline phosphatase moderate elevations
- 3 – 10 fold normal value
| - Obstruction by stones
56
Hepatic alkaline phosphatase mild elevations
- 1-3 fold normal values
- Alcoholic liver disease
- Chronic active hepatitis
- Viral hepatitis
57
Bilirubin reference values
- Total: 0.3-1.9 mg/dl
| - Direct: 0 to 0.3 mg/dl
58
Bilirubin (extrahepatic liver function)
- Breakdown product of hemoglobin catabolism
- Occurs within Kupffer cells via cytochrome P-450
- Transported in its inactive state on albumin
59
Free or indirect bilirubin elevates with
- Lack of serum albumin
- Red cell hemolysis
- Hepatitis
- Gilbert’s syndrome
60
Free or indirect bilirubin
- Diffuses freely through BBB
| - Jaundice
61
Conjugated or direct bilirubin
- Conjugated in the hepatocytes with glucuronic acid
62
Conjugated or direct bilirubin elevates with
- Biliary obstruction
- Pancreatitis
- Lymphoma
63
Tiglycerides (extrahepatic liver function)
- Reference values:
10-190 mg/dl
- Wiggin1 correlated elevated triglycerides levels with DPN (this loss was independent of glycemic control and duration of disease)
64
Blood urea nitrogen (BUN) reference value
- 9-27 mg/dl
65
BUN (renal functionP)
- End product of amino group removal in degradation of amino acids
- Urea is freely filtered by the glomerulus
- Moves through renal tubules via passive diffusion intra renal cycling (60% is reabsorbed, 40% is secreted)
66
BUN clinical significance
- Elevates with severe glomerular injury
| - Decreases with severe liver damage (severe poisoning, hepatitis)
67
Elevated BUN at higher limits
- Quite sensitive
| - >25 mg/100 ml suggests ~25% nephrons damages
68
Creatinine (renal function) reference value
- 0.5-1.5 mg/dl
69
Creatinine (renal function)
- Most sensitive indicator of glomerular filtration
- End product of creatine catabolism (Creatine-PO3 + muscle contraction -> creatinine)
- Nearly filtered completely by the kidney
- Ideal to measure glomerular filtration rate
70
Sodium (serum electrolyte)
- Major cation in extracellular fluid
| - Principal osmotic particle outside cell
71
Hyponatremia
- Overhydration
- Loop diuretics
- Increased secretion of antidiuretic hormone
- Adrenal failure
72
Hypernatremia
- Excessive water loss – dehydration
- Renal losses
- Diabetes insipidus
73
Hypo/hypernatremia reference range
- 135 – 145 mEq/l
- Symptomatic hyponatremia: < 120 mEq/l
- Symptomatic hypernatremia: 150 – 170 mEq/l
74
Potassium (serum electrolyte)
- Major intracellular cation
| - Abnormal values profoundly affect neuromuscular system
75
Hypokalemia
- Serum depletion of potassium
- Renal losses
- Presence of EKG U-wave
76
Hyperkalemia
- Acute and chronic renal failure
- High concentration in RBC’s
- Presence of peaked T-waves
77
Potassium reference range
- 3.5-5.5 mEq/l
78
Hypochloridemia
- GI losses
- Diabetic ketoacidosis
- Mineral corticoid excess
- Respiratory acidosis
- Metabolic alkalosis
79
Hyperchloridemia
- GI loss from diarrhea
- Mineral corticoid deficiency
- Hyperparathyroidism
80
Chloride reference range
- 98-106 mEq/l
81
Serum bicarbonate elevates with
- Metabolic alkalosis
- Comp. respiratory acidosis
- Diuretics
- Corticosteroids
82
Serum bicarbonate decreases with
- Metabolic acidosis
- Comp. respiratory alkalosis
- Salicylate poisoning
83
Serum bicarbonate reference range
- Arterial: 19-25 mEq/l
| - Venous: 23-30 mEq/l
84
Anion gap equation
- Anion Gap = [Na+ + (*K+)] – [Cl- + HCO3-]
85
Anion gap elevated with
- Uremia
- Diabetic ketoacidosis
- Starvation states
- Ingestions of toxins (Methanol, Salycilates, Ethylene glycol)
86
Anion gap decreased with
- Dilutional states
- Hyperviscosity syndromes
- Lithium intoxication
87
Anion gap reference range
- Reference range: 8 - 12 mEq/l
| - May be calculated without serum potassium
88
Uric acid
- End product of purine catabolism
| - Renal excretion
89
Uric acid reference values
- Male: 4.0 – 8.5 mg/dl
| - Females: 2.7-7.3 mg/dl
90
Uric acid accumulation is predominantly a male disease
- Estrogens are protective
- Solubility of crystals decrease with body temperature
- 37 C – solubility 6.8 mg%
- 30 C – solubility 4.5 mg%
91
Gout
- Ingestion of crystal by neutrophil
| - Negatively birefringent
92
Gouty arthritis and draining tophi
- Patient with endstage renal disease
- Unable to tolerate allopurinal
- Currently started Uloric - febuxostat
93
Globular proteins (total serum proteins)
- Albumin (55-60%)
- Globulins
- Synthesized in liver
- Source of stored protein
94
Globulins
- Immunoglobulins
- Lipoproteins
- Fibrinogen
- Hemoglobin
- Cytochromes
95
Total serum protein
- Insight to nutritional status
| - Reference range: 6.0-8.5 g/dL
96
Low serum protein
- Starvation states
- Inability of liver to synthesize proteins
- “Leaky” glomerular filtration
97
Albumin role
- Maintenance of plasma oncotic pressure
- “Transport” protein
- Substances are inactive when bound to albumin
98
Decreased albumin levels
- Inability of liver to synthesize
| - Poor nutritional status
99
Albumin level clinical significance
- Large body pool with a T1/2 of ~20 days
| - Affected by hydration and renal status (chronic liver disease, malnutrition)
100
Albumin reference value
- 3.5-5.5 g/dL
101
Prealbumin
- Preferred marker for protein malnutrition
- Less affected by liver disease
- Distinct marker for protein synthesis
- Not affected by hydration status
- Very high ration of essential to non-essential amino acids
102
Prealbumin clinical interpretation
- Normal range: 10.5-35.0 mg/dl
- Increased risk for morbidity: 5.0-15.0 mg/dl
- Poor prognosis: < 5.0 mg/dl
- Increased 2.0 mg/dl/day with supplementation
103
Serum transferrin
- Half life of one week
- Responds more quickly to nutritional status changes
- Serum transferrin is determined two site enzyme immuno-assay
- Measuring total iron binding capacity is roughly equivalent to transferrin
104
Total iron binding capacity (TIBC) is determined by
- Saturating transferrin with iron
- Removing the unbound iron
- Measuring the iron in the infiltrate
105
TIBC increases in
- Iron deficiency anemia
- Pregnancy
- Oral contraceptives
- Possibly hepatitis
106
TBIC decreases in
- Reduced protein synthesis, nephrosis or other direct loss
| - Increased catabolism (secondary to malignancy or starvation)
107
Alkaline phosphatase
- Released by osteoblasts actively secreting bone matrix
108
Pronounced elevation of alkaline phosphatase
- 5 fold or greater
- Osteitis deformans
- Osteogenic sarcoma
- Hyperparathyroidism
109
Moderate elevation of alkaline phosphatase
- 3 – 5 fold greater
- Metastatic bone tumors
- Metabolic bone diseases
110
Slight elevation of alkaline phosphatase
- Healing fractures
- Growth spurts
- Pregnancy
111
Calcium
- Most abundant cation in body
| - Reference values: 9.2-11 mg/dl
112
Calcium levels are regulated by
- Kidney
| - Parathyroid hormones
113
Hypocalcemia
- Renal failure (increased phosphorus)
| - Hypoparathyroidism
114
Hypercalcemia (CHIMPS)
- Cancer
- Hyperthyroidism
- Iatrogenic
- Multiple myeloma
- Parathyroidism
- Sarcoidosis
115
Phosphorous levels are controlled by
- PTH
- 1, 25- dihydroxycholicalciferol
- Calcitonin
116
Decreased levels of phosphorous
- Diabetic ketoacidosis
- Hyperinsulinism
- Hyperparathyroidism
- Inadequate diet
117
Increased levels of phosphorus
- Bone metastasis
- Hypoparathyroidism
- Liver disease
- Renal failure
- Sarcoidosis
118
Three isoenzymes of creatinine kinase (cardiac)
- MB – myocardial injury
- MM – skeletal muscle
- BB – brain
119
Cardiac elevations of creatinine kinase
- CK-MB band elevates during first 48 hours
- Along with LDH “flip” quite reliable (LDH1 >LDH2)
- Myoglobin will be elevated before CK-MB band
- Cardiac troponins (I elevates 5 – 9 days, T elevated up to 2 weeks)
120
Skeletal muscle damage
- CK-MM band elevation
| - Elevation of aldolase
121
Elevation of aldolase
- Glycolytic enzyme
| - Most useful for inflammatory muscle disease
122
Elevations of aldolase also secondary to
- Metastatic carcinoma
- Granulocytic leukemia
- Megaloblastic anemia
- Hemolytic anemia
123
Pancreatic (P form) amylase
- Levels rise within 6-24 hours and return to normal within 48-72 hours
- Does not correlate with severity of disease
124
Pronounced amylase elevations
- > 5 times normal values
- Acute pancreatitis
- Administration of morphine
125
Moderate amylase elevations
- 3-5 times normal values
- Pancreataic carcinoma
- Salivary gland disease
126
Pancreatic amylase reference values
- 30-220 u/l
127
Pancreatic lipase
- Diagnostic for acute pancreatitis
- Cleaves triglycerides into free fatty acids
- Nearly exclusive to pancreas
- Will elevate with heparin administration
128
Pancreatic lipase reference value
- 0-417 u/l
129
Fasting glucose values
- Diabetes: > 126 mg/dl
- Glucose impaired: 100-126 mg/dl
- Normal: <100 mg/dl
130
Glucose tolerance values
- Diabetes: >200 mg/dl
| - Glucose impaired: 140-200 mg/dl
131
Casual glucose values > 200 mg/dl on two occasions
- Increased thirst
- Increased hunger
- Unexplained weight loss
132
Glycosylated hemoglobin
- Glycosylation of β-chain of Hb
- Window into past three months
- Reference values: < 6%
133
Glycosylated albumin
- Glycosylation of serum proteins
- Window into past 2-3 weeks
- Reference values: Albumin < 8%, total serum proteins < 3%
134
C-peptide measurements
- Indicator of endogenous insulin production
| - Assesses integrity of islet cells
135
C-peptide serum ratios
- Normal = 15:1
- Normal to high = Type 2
- Absent to low = Type 1
136
A1C levels
- Diagnostic indicator of diabetes Type II
- ≥ 6.5% = diabetes
- 5.7 - 6.4% = prediabetes
- < 5% = normal non-diabetic
137
Glycosylated albumin properties
- Serum half-life 17-20 days
- Reflects hyperglycemic periods within the previous few weeks
- Up to 8% may be normally glycosylated
138
New studies on A1C to glycated albumin
- Suggest that an A1C to glycated albumin ratio may provide a better insite into glucose control
139
C-reactive protein (CRP) acute phase reactant is an indicator for
- Inflammatory process (rapid rise with acute disease, rapid clearance with resolution of process)
- Future coronary events
140
CRP future coronary event indicators
- < 1 mg/L = low risk
- 1-3 mg/L = average risk
- > 3 mg/L = high risk
141
Homocysteine
- Variant of cysteine
142
Elevated homocysteine levels result in
- Oxidation of low density lipoproteins
- Increased clot formation
- Endothelial damage
143
Causes of homocysteine high levels
- Nutritional deficit of folate, pyridoxine and B12
- Hereditary homocysteinuria
- Methyl-tetrahydrofolate reductase deficiency
144
Complement measurements
- Circulate until cascade is initiated
| - C1, C3 and C4 are most plentiful
145
Low levels of complement
- Indicative of antibody-antigen mediated process
- Collagen vascular diseases
- Connective tissue disease
146
High levels of complement
- Cancer
| - Ulcerative colitis
147
Synovial fluid analysis
- Sterile preparation of joint
| - Transport in heparin or EDTA tube
148
Synovial fluid analysis evaluated on
- Color/clarity
- Viscosity
- Total WBC and % PMN’s
- Presence of formed elements
- Mucin clot retraction
149
Synovial fluid elements
- Normal = none
- OA = collagen fibrils
- Traumatic DJD = many RBCs
- SLE = LE cells
- RA = cholesterol crystals
- Pseudogout = Calcium pyrophosphate crystals
- Gout = monosodium urate crystals
150
Synovial fluid infection
- WBC: >50,000 cells/μl
- Normal: PMN < 25%
- Infection: PMN > 90%
- Glucose: 25 mg/dl lower than serum levels
151
Urinalysis specific gravity
- Ion concentration of urine
- Reflects concentrating ability of kidneys
- Reference: 1.010-1.030
152
Urinalysis color and appearance
- Normal color – yellow
| - Normal appearance - clear
153
Urinalysis pH
- Reflects renal acid excretion
- Dependent on dietary intake
acidic – high protein diets, -DM, tubular acidosis
- Alkaline – UTI’s
- Reference: 4.8-7.5
154
Urinalysis protein
- No protein in urine
| - No reference to trace
155
Urinalysis protein 2+
- Glomerular disease
| - Urinary tract disorder
156
Urinalysis protein 2-4 g/day
- Collagen vascular disease
- Congestive heart failure
- Nephrotic syndrome
157
Urinalysis glucose
- A significant index of hyperglycemia
- No reference to trace
- Not sensitive to glucose
158
Urinalysis not sensitive to glucose due to
- Incomplete bladder empyting
- Concomitant renal disease
- Serum glucose levels are > 200-250 before detected
159
Urinalysis ketones
- Reflect the use of fatty acid metabolism
- Presence important in starvation states and diabetes mellitus
- Reference: 0-160 mg/dl
160
Urinalysis hemoglobin and red cells
- Trauma, infection, glomerular damage
| - Reference: 0-3 cells/hpf
161
Urinalysis bilirubin
- Only conjugated bilirubin appears in urine
| - Reflects biliary obstruction
162
Urinalysis urobilinogen
- Elevated with hemolysis and most liver diseases
| - Decreased with antibiotics and bile duct obstruction
163
Urinalysis leukocyte esterase
- Released by WBC’s responding to infection
164
Urinalysis nitrates
- Byproduct of vegetable ingestion
| - Some bacteria convert nitrate to nitrite
165
Casts in microscopic examination of urinalysis
- Suggest renal tubular damage
| - Debris collects in tubules
166
Granular debris in tubules
- Plasma protein aggregates that escape through damaged tubules
167
Fatty debris in tubules
- Significant proteinurea
168
Waxy debris in tubules
- Oliguria
| - Nephron obstruction
169
Hyaline debris in tubules
- Glomerular capillary damage
170
White blood cells in urinalysis microscopic examination
- Suggests inflammation or infection
171
Epithelial cells in urinalysis microscopic examination
- Represent desquamation of urinary tract epithelial cells
- May represent poorly collected specimen
- Renal tubular cells abnormal
172
Microalbuminuria collection techniques
- Albumin to creatinine ratio from random sample
- 24 hour collection with creatinine
- Timed collection (min. 4 hrs)
173
Elevation in microalbuminuria
- Early sign of renal disease
174
Microalbuminuria reference values
- < 30 – normal
- 30 – 299 – microalbuminuria
- >300 – albuminuria
175
Microalbuminuria hypertensive patients
- Should be placed on ACE or ARB meds
176
Urinary 24 hour calcium
- Reflects intestinal absorption of calcium or renal leakage
177
Low levels of urinary 24 hour calcium
- Underactivity of parathyroid gland
- Check parathyroid – if normal…evaluate 25 hydroxy Vitamin D
- Inadequate intake of vitamin D
178
Urinary 24 hour calcium reference values
- Low - < 150 mg
- Average – 150-250 mg
- High – 250-300 mg
179
Systemic inflammatory response syndrome (SIRS) criteria
- Evaluation of the physiologic response to inflammation
- Temperature < 36° C or > 38° C
- Heart Rate > 90 bpm
- Respiratory Rate > 20 breaths/minor PaCO2 < 32 mm/Hg
- White Blood Cell Count > 12,000 or < 4,000 cells/mm3 or > 10% bands
- Minimum of 2 of above for SIRS diagnosis
180
Septic shock criteria
- Trauma = SIRS
- Sepsis = SIRS, infection
- Severe sepsis = sepsis, organ failure, hyoptension, hypoperfusion
- Septic shock = sepsis with hypotension, 2+ organ failure
181
Procalcitonin (PCT)
- Helps identify SIRS from sepsis
- More specific than CRP, IL-6 and LBP
- May help guide antibiotic therapy
182
Procalcitonin (PCT) levels
- < 2 ng/ml – can exclude sepsis (NPV – 97%)
| - > 10 ng/ml – bacterial infection likely (PPV – 88%)
183
Laboratory risk indicator for necrotizing fasciitis (LRINEC score)
- Help discriminate between necrotizing and non-necrotizing infections
- Six independent variables with an applied point system
184
LINREC score
- Range from 0 – 13
- Intermediate to high risk if the score was >6
- Utilized when there is a high index of suspicion
185
Necrotizing fasciitis risk category
- Low = ≤ 5 total score, < 50% probability of NF
- Intermediate = 6 – 7 total score, 50 – 75% probability of NF
- High = ≥ 8 total score, > 75% probability of NF
