Lab Values & Drug Monitoring Flashcards
True or false: Home test kits exist for things like HIV and herpes, fecal occult blood
True.
What is therapeutic drug monitoring?
Obtaining a drug level or other relevant labs to monitor efficacy and safety
Often performed by pharmacists
CBC vs CBC with differential
Complete blood count panel analyzes white blood cells aka neutrophils, along with red blood cells, and platelets
CBC with differential analyzes the types of neutrophils which are types of WBCs
BMP
Basic metabolic panel (think of the fish skeleton model)
7-8 tests that analyze the electrolytes, glucose, renal function & acid base with bicarbonate status, sometimes anion gap is calculated too
BMP and CMP can be ordered together for convenience
CMP
Comprehensive metabolic panel includes BMP tests + albumin , alanine aminotranferase (ALT), aspartate aminotransferase (AST), total albumin, and total protein
BMP and CMP can be ordered together for convenience
Stem cells (hematopoetic cells) in the bone marrow produce which kinds of cells
WBCs aka leukocytes, RBCs aka erythrocytes, and PLTs
Immature RBCs are called reticulocytes
What are the types of WBCs
Types of white blood cells are granulocytes (neutrophils, eosinophils, and basophils), monocytes, and lymphocytes (T cells and B cells)
Never
Let
Monkeys
Eat
Bananas
Describe the layout of the stick diagrams for the fish bone and the cat whiskers
Fishbone:
Na|Cl- |BUN|
K+ |HCO3-|SCr. | Glu
Cat whiskers”
WBC. Hbg/Hct Plt
Define leukocytosis
increased WBCs
Define polycythemia
increased RBCs
Define thrombocytosis
increased PLTs
Define leukopenia
decreased WBCs
Define Anemia
decreased RBCs and Hgb
Define thrombocytopenia
decreased platelets
Define myelosuppression
decreased WBCs, RBCs, and PLT’s
Define agranulocytosis
Decreased granulocytes (WBCs with granules: neutrophils, eosinophils, and basophils)
Drugs that cause agranulocytosis
Clozapine
Propylthiouracil
methimazole
procainamide
carbamazepine
sulfamethoxazole/trimethoprim
isoniazid
Total Ca+ normal range
8.5 - 10.5 mg/dL
Ionized Ca+ normal range
4.5 -5.1 mg/dL
If ionized Ca+ is below normal range, do we need to calculate corrected calcium?
No. We would only need to if the albumin is low and we have the total calcium value. Ionized calcium does not require correction.
T or F? Calcium should be supplemented in pregnancy and in osteoporosis/osteopenia and certain drugs
True girl.
What are reasons Ca+ levels increase
Vitamin D or calcium supplementation, or thiazide diuretics
What are reasons Ca+ levels decrease
long term heparin use, loop diuretics, bisphosphonates, cinacalcet, systemic steroids, calcitonin, foscarnet, and topiramate
Normal chloride levels
95-106 mEq/L - helps us understand acid bace and fluid balance
Normal Mg levels
1.3 - 2.1 mEq/L
Reasons for Mg increasing
Related to mg containing antacids and laxatives, risk is higher with renal impairment
Reasons for Mg decreasing
Related to PPIs, diuretics, amphotericin B, foscarnet, echinocandins, diarrhea, chronic alcohol intake
Normal phosphate levels
2.3 - 4.7 mEq/L
Reasons for Phosphate level increase
CKD
Reasons for phosphate level decrease
phosphate binders, foscarnet, oral calcium intake
Normal K+ levels
3.5-5 mEq/L
Reasons for K+ increase
ACE inhibitors, ARBs, aldosterone receptor antagonists (ARAs), aliskiren, canagliflozin, cyclosporine, tacrolimus, mycophenolate can increase and decrease, potassium supplements, sulfamethoxazole/trimethoprim, drospirenone- containing oral contraceptives, chronic heparin use, NSAIDS, pentamidine
Reasons for K+ decrease
Beta-2 agonists, diuretics, insulin, steroids, conivaptan, mycophenolate can increased and decrease
Normal Na+ levels
135-145 mEq/L
Reasons for Na+ increase
hypertonic saline, tolvapatan, conivaptan
Reasons for Na+ decrease
carbamazepine, oxcarbazepine, SSRIs diuretics, desmopressin
Normal range for bicarbonate (venous and arterial) and why do we use it
venous: 24-30 mEq/L
arterial: 22-26 mEq/L
used to assess acid base status
Reasons for bicarbonate increase
loop diuretics and systemic steroids
reasons for bicarbonate decrease
topiramate, zonisamide, and salicylate overdose
Normal BUN levels (blood urea nitrogen)
7-20 mg/dL
Used in ratio with SCr to assess fluid status and renal function
Reasons for BUN increase
renal impairment and dehydration
Normal range for Scr
0.6-1.3 mg/dL
Reasons for SCr increase
drugs that impair renal function (aminoglycosides, amphotericin B, cisplatin, colistimethate, cyclosporine, loop diuretics, polymixin, NSAIDs, radiocontrast dye, tacrolimus, vancomycin)
False increase: bactrim, H2RAs colbicistat
reasons for Scr decrease
low muscle mass
amputation
hemodilution
Normal anion gap range and reason for use
5-12 mEq/L
Tells us if theres a “gap” or mistake in the balance of electrolytes and helps to define if theres a metabolic problem (increased value = metabolic acidosis)
Normal wbc range and what is it used for
4000 - 11000 cells / mm^3
used to diagnose and monitor infection and inflammation
Reasons for WBC increase
acute phase reactant (inflammatory marker increases in serum after event like surgery), infection
systemic corticosteroids, colony stimulating factors, epinephrine
Reasons for WBC decrease
clozapine, chemotherapy for bone marrow, carbamezapine, cephalosporins, immunosuppressants (e.g. DMARDs like MTX, biologics, etc.), procainamide, vancomycin
Normal neutrophil (aka polymorphonuclear cell - PMNs or Polys or segmented neutrophils “segs”) range and how do we use it
45-73%
Used with clinical s/sx to assess the presence of an acute infection. Can be used in ANC formula (absolute neutrophil count).
Normal bands range and what are they used for
3-5%
They are immature neutrophils released from the bone marrow to fight infection. When these are elevated, it’s called a left shift
normal eosinophil range
0-5%
reasons for eosinophil increase
drug allergy
asthma
inflammation
parasitic infection
normal basophil range
0-1%
reasons for increase in basophils
inflammation
hypersensitivity reaction
leukemia
normal lymphocyte range
20-40%
Bcells and Tcells
Reasons for lymphocyte increase
viral infections
lymphoma
Reasons for lymphocyte decrease
bone marrow suppression, HIV, systemic corticosteroids
Normal monocyte range
2-8%
Reason for monocyte increase
chronic infections
inflammation
stress
Why do we care about therapeutic drug monitoring
We need to reach adequate drug therapy without causing toxicity. We need to account for underweight/overweight/obese patients
Define drug peak
The highest concentration the drug will reach in the blood and this requires time to distribute into the body’s tissue
It’s ideal to obtain the drug level at steady state
Define drug trough
The lowest concentration the drug will reach in the blood and it’s drawn right before the next dose or like 30 min before. This gives time to assess the concentration and see if giving the next dose is appropriate
Its ideal to obtain the drug level at steady state
Narrow therapeutic index means
Drugs that have a small range between subtherapeutic (not working), therapeutic, and supratherapeutic (toxic)
Usual therapeutic range for Carbamazepine
4-12 mcg
Usual therapeutic range for Digoxin
0.8- 2 ng/mL in Afib
0.5-0.9 ng/mL in heart failure
Usual therapeutic range for Gentamicin traditional dosing AND tobramycin traditional dosing
Peak: 5-10 mcg/mL
Trough: <2 mcg/mL