SERUM
CALCIUM
Ø Physiology
o Parathyroid Hormone(PTH) modulates Serum
Calcium
o PTH rises in response to low calcium
o PTH falls in response to high calcium
Total body calcium distribution
Ø Skeleton: 98%
Ø Circulating: 2%
Ø Free or ionized Serum Calcium (active): 50%
Ø Albumin-bound Serum Calcium (inactive): 50
Normal (normal range varies by
individual labs)
Ø Serum Calcium: 8 to 10 mg/dl
Ø Ionized (free) Calcium: 4 to 5.6 mg/dl
Abnormal
Hypercalcemia
Ø Mild: Serum Calcium 10.5 to 12 mg/dl
Ø Moderate: Serum Calcium 12 to 14 mg/dl
Ø Critical: Serum Calcium 14 mg/dl or higher
Hypocalcemia
Ø Serum Calcium under 8.0 mg/dl
Serum
Uric Acid
Physiology
Uric
Acid is a metabolic-by-product of purine catabolism
Normal
·
Uric
Acid: 2-7 mg/dl
Increased
·
Hyperuricemia
Decreased:
·
Drugs-Allopurinol,High
dose ASA, Cortico steroids
·
Renal
tubule disease
·
Alcohol
·
Wilson’s
Disease
·
Hemochromatosis
·
Protein
or purine deficient diet
·
Xanthine-oxidase
deficiency
Serum
Potassium
Normal
3.5-5.0
mEq/L
Abnormal
Hyperkalemia
·
Pseudo
hyperkalemia
·
Hyperkalemia
due to decreased renal excretion
·
Hyperkalemia
due to redistribution
·
Hyperkalemia
due to excessive potassium load
·
Hyperkalemia
due to medicine
Hypokalemia
·
Renal
potassium loss
·
Extra
renal potassium loss
·
Tran
cellular potassium shift
Serum Sodium
Normal
135-147 mEq/L
Abnormal
Hypernatremia:
Serum Sodium over 147
Hyponatremia:
Serum Sodium under 135
Pathophysiology
Serum
Chloride 1 meq/L drop: 1% all body Chloride fall
Causes
Ø Metabolic Alkalosis
Ø Vomiting
Ø Diarrhea
Ø Diuretics
Ø Respiratory losses
Ø Steroid medications
Ø Hyponatremia
Ø Adrenal
insufficiency(Addison’s disease)
Ø Edematous states
Ø Congestive Heart Failure
Ø Salt-losing nephritis
Ø Renal Failure
Ø Excessive sweating
Ø Burns
Serum
Troponin
Serum Cardiac Markers
Dynamics
Ø Rises: 3-6 hours
Ø Peaks: 20 hours
Ø Duration: 14 days
Subunits
Ø Troponin T
Ø Troponin I
Troponin T
Epidemiology
Ø Sensitivity: 94% of Myocardial infarctions
Ø Specificity: Low (22% have Unstable Angina)
Advantages
Ø Highly sensitive for detecting MI
Disadvantage
Ø Less specific than Troponin I Elevated in
Unstable Angina
Ø Elevated in Chronic Renal Failure
Ø Levels stay elevated for days
Ø Unable to time acute coronary event
Troponin I
Ø Sensitivity: 100% of Myocardial Infarctions
Ø Specificity: Low (36% have Unstable Angina
Advantages
Ø More specific than Troponin T
Ø Not falsely elevated in Chronic Renal Failure
I
Ø nterpretation Level >1.0 to 1.2 suggestive
of Myocardial Infarction
Serum
Estradiol
Normal Levels
Ø Male: 6 to 46 pg/ml
Ø Female
Follicular Phase: 30 to 90 pg/ml
Luteal Phase : 70 to 300 pg/ml
Prolactin
Normal Levels
Ø Adult: <20 ng/ml
Ø Newborn: 100 to 300 (falls below 20 after 6
weeks)
Ø Pregnancy
First Trimester: <80 ng/ml
Second trimester: <160 ng/ml
Third Trimester: <400 ng/ml
Lactation
Ø Initially (<3 months postpartum)
Ø First week: 100 ng/ml basal level
Ø First 1-2 months: 50 ng/ml basal level
Suckling raises Prolactin 10-20 fold above basal level
Ø Later (3-6 months post-partum) Suckling may
double basal level
Serum
Testosterone
Normal Levels
Ø Male: 300 to 1000 ng/100 ml
Ø Female: <70 ng/100 ml
Carcino
Embryonic Antigen: CEA
A substance often found in a person with
cancer
Tumor Marker
Indications
Ø Stage II or III (Duke B1-C1) Colon Cancer
monitoring
Ø Do not use to screen for Colon Cancer or other
cancer
Interpretation
Normal
Ø Non-smokers: <2.5 mg/ml
Ø Smokers: <5 ng/ml
Increased
Ø Benign disease unlikely if >10 ng/ml
Ø Distant metastasis most likely if >100
ng/ml
Causes of increased CEA
Ø Benign Causes
Ø Tobacco abuse
Ø Peptic Ulcer Disease
Ø Inflammatory Bowel Disease
Ø Pancreatitis
Ø Hypothyroidism
Ø Cirrhosis
Malignant causes
Ø Colon Cancer
Ø Breast Cancer
Ø Gastric Cancer
Ø Lung Cancer
Ø Pancreatic Cancer
Ø Bladder Cancer
Ø Cervical Cancer
Ø Melanoma
Ø Lymphoma
Serum
Ferritin
Indications
Evaluation
for Iron Deficiency Anemia
Physiology
Ø Indicator of total body iron stores
Ø Most reliable indicator other than Bonemarrow
Ø Acute phase reactant
Normal
Ø Range: 18-300 ng/ml
Increased
ü Inflammatory states
ü Hyperthyroidism
ü Liver disease (necrotic hepatocytes)
ü Hodgkin’s and Non Hodgkin’s Lymphoma Leukemia
ü Breast Cancer
ü Neuroblastomas
ü Hemochromotosis
ü Iron Supplementation
ü Still’s Disease(very high, Ferritin >5000)
