Lab values Flashcards
Calcium (total and ionized)
8.5- 10.5 mg/dL (total)
4.5-5.1 mg/ dL (ionized)
Calculate corrected calcium if albumin is low (not needed for ionized calcium).
Increase due to calcium supplementation, vitamind D, thiazide diuretics
Decrease due to long term heparin, loop diuretics, bisphosphonates, cinacalcet, systemic steroids, calcitonin, foscarnet, topiramate
Supplement in pregnancy osteoporosis/osteopenia and with certain drugs
Chloride
95-106 mEq/L
Used with other labs to assess acid-base status and fluid balance.
Magnesium
1.3-2.1 mEq/L
increase due to magnesium-containing antacids and laxatives (higher risk with renal impairment)
decrease due to PPIs, diuretics, amphotericin B, foscarnet, echinocandins, diarrhea, chronic alcohol intake
Phosphate
2.3-4.7 mg/dL
increase in chronic kidney disease
decrease due to phosphate binders, foscarnet, oral calcium intake
Potassium
3.5-5 mEq/L
increase due to ACE inhibitors, ARBs, aldosterone receptor antagonists, aliskiren, canagliflozin, cyclosporine, tacrolimus, potassium supplements, sulfamethoxazole/trimethoprim, drospirenone-COC
decrease due to beta 2-agonists, diuretics, insulin, sodium polystyrene sulfonate
Sodium
135-145 mEq/L
increase due to hypertonic saline, tolvaptan, conivaptan
decrease due to carbamazepine, oxcarbazepine, SSRIs, diuretics, desmopressin
Sodium level may require correction when hyperglycemia is present
Bicarbonate
venous: 24-30 mEq/L
arterial: 22-26 mEq/L
Used to assess acid-base status
Increase due to loop diuretics, systemic steroids
decrease due to topiramate, zonisamide, salicylate overdose
Blood Urea Nitrogen
7-20 mg/dL
increase in renal impairment and dehydration. Used with SCr to assess fluid status and renal function
Serum Creatinine
0.6-1.3 mg/dL
increase due to may drugs that impair renal function (aminoglycosides, amphotericin B, cisplatin, colistimethate, cyclosporine, loop diuretics, polymyxin, NSAIDs, radiocontrast dye, tacrolimus, vancomycin
false increase due to sulfamethoxazole/trimethoprim, H2RAs, cobicistat
decrease with low muscle mass, amputation, hemodilution
Glucose
70-110 mg/dL
Anion Gap
5-12 mEq/L
calculated value, often reported on the BMP.
An increased anion gap suggests metabolic acidosis
White blood cells
4,000-11,000 cells/mm3
Can increase as an acute phase reactant, indicating a systemic reaction to inflammation or stress
increase due to systemic steroids, colony stimulating factors, epinephrine
decrease due to clozapine, chemotherapy that targets bone marrow, carbamazepine, cephalosporins, immunosuppresants (DMARDs, biologics), procainamide, vancomycin
Neutrophils
45-73%
Used (w signs + symptoms) to assess the likelihood of acute infection. They are also used (w WBC) in the absolute neutrophil count cl to assess for neutropenia
Neutrophils are also called polymorphonuclear cells or segmented neutrophils
Bands
3-5%
Bands are immature neutrophils released from the bone marrow to fight infection (called ‘left shift’ when elevated)
Eosinophils
0-5%
Increase in drug allergy, asthma, inflammation, parasitic infection
Basophils
0-1%
increase in inflammation, hypersensitivity reactions, leukemia
Lymphocytes
20-40%
increase in viral infections, lymphoma
decrease in bone marrow suppression, HIV or due to systemic steroids
monocytes
2-8%
increase in chronic infections, inflammation, stress
Red blood cells
Males: 4.5-5.5 x 106 cells/ uL
Females: 4.1-4.9 x 106 cells/uL
RBCs have an average life span of 120 days
Increase due to erythropoiesis-stimulating agents (ESAs), smoking, and polycythemia
Decrease due to chemotherapy that targets the bone marrow, low production, blood loss, deficiency anemias (B12, folate), hemolytic anemia, sickle cell anemia
Hemoglobin
Males: 13.5-18 g/dL
Females: 12-16 g/dL
Hgb is the iron containing protein that carries oxygen in RBCs
increase due to ESAs
decrease in anemias and bleeding (drug-induced cuases include anticoagulants, antiplatelets, fibrinolytics)
Hematocrit
Males: 38-50%
Females: 36-46%
Hct mirrors the Hgb result
increase due to ESAs
decrease in anemias and bleeding (drug-induced cuases include anticoagulants, antiplatelets, fibrinolytics)
Mean Corpuscular Volume
80-100 fL
Reflects the size and average volume of RBCs
increase (macrocytic anemia) due to B12 or folate deficiency
decrease (microcytic anemia) due to iron defiviency
Mean Corpuscular Hemoglobin
26-34 pg/cell
Additional tests used in an anemia workup
Mean corpuscular Hgb concentration
31-37 g/dL
Additional tests used in an anemia workup
RBC distribution width
11.5-14.5%
RDW measures the variability in the RBC size
iron
65-150 mcg/dL
increase due to iron supplementation. decrease due to blood loss or poor nutrition
Total iron binding capacity
250-400 mcg/dL
Transferrin
> 200 mg/dL
Transferrin Saturation
Males 15-50%
Females: 12-45%
Ferritin
11-300 ng/mL
Erythropoietin
2-25 mIU/mL
Folic acid (folate)
5-25 mcg/L
decrease due to phenytoin/fosphenytoin, phenobarbital, primidone, methotrexate, sulfamethoxazole/trimethoprim, sulfasalazine
supplement folate in women of childbearing age and alcohol use disorder
Vitamin b12
> 200 pg/mL
decrease due to PPis, metformin, colchicine, chloramphenicol
Methylmalonic Acid
varies
used for futher workup of macrocytic anemia when B12 deficiency is suspected
Reticulocyte
0.5-2.5%
Measures the amount of reticulocytes being made by the bone marrow
increase with blood loss and hemolysis. decrease in untreated anemia, due to iron, folate or B12 deficiency, and with bone marrow suppression
Coombs Test, Direct
Direct antiglobulin test
Negative
used in the diagnosis of immune-mediated hemolytic anemia
Drugs that can cause immune-mediated hemolytic anemia include penicillins and cephalosporins (prolonged use/ high concentrations) isoniazid, levodopa, methyldopa, quinidine, quinine, rifampin and sulfonamides
Glucose
5-14 units/gram
Used to determine if hemolytic anemia is due to G6PD deficiency. RBC destruction with G6PD deficiency s triggered by stress, foods (fava beans) or these drugs: dapsone, methylene blue, nitrofurantoin, pegloticase, primaquine, rasburicase, quinidine, quinine, and sulfonamides
Anti-factor Xa Activity
Terapeutic doses of LMWH (obtain a peak anti-Xa level 4 hours after a SC LMWH dose): 1.0-2.0 IU/mL
Unfractionated heparin (obtain 6 hours after IV infusion starts and every 6 hours until therapeutic): 0.3-0.7 IU/mL
Used to monitor low molecular weight herparins (LMWH) and unfractionated heparin
Monitoring for LMWH is recommended in pregnancy and may be used in obesity, low body weight, pediatrics, elderly, renal insufficiency
Prothrombin time / internation normalized ratio (PT/INR)
PT: 10-13 seconds
INR: < 1.2 (if not on warfarin)
Used to monitor warfarin
INR increase typically due to liver disease
False increase can occur with daptomycin, oritacancin, telavancin
Activated Partial Thromboplastin Time (aPTT or PTT)
22-38 seconds
UFH: obtain 6 hours after IV infusion starts and every 6 hours until therapeutic
Goal (on UFH): 1.5-2.5x control
Used to monitor UFH and parenteral direct thrombin inhibitors (argatroban)
False increase can occur with oritavancin, tekavancin
Activated Clotting Time
70-180 seconds
Used to monitor anticoagulation in the cardiac catheterization lab during percutaneous coronary intervention and surgery
Platelets
150,000-450,000 cells/ mm3
Avg lifespan of 7-10 days. Platelets are required for clot formation. Spontaneous bleeding can occur when platelets are < 20,000 cells/mm3
decrease due to heparin, LMWH, fondaparinux, glycoprotein IIb/IIa receptor antagonists, linezolid, valproic acid, chemotherapy that targets the bone marrow
Heparin Induced Platelet Antibodies
ELISA test 1st then an serotonin release assay
Negative
Heparin induced thrombocytopenia is suspected when platelets drop > 50% from baseline as a result of treatment wit UFH or LMWH
Antibody testing is used to confirm a diagnosis of HIT. If the ELISA test is positive, a positive SRA is confirmatory
Albumin
3.5-5 g/dL
decrease due to cirrhosis and malnutrition
Serum levels of highly protein-bounf drugs (warfarin, calcium, phenytoin) are impacted by low albumin. Phenytoin and calcium conc require correction for low albumin. A free phenytoin level or ionized calcium does not require adjustment
Alkaline phosphate
33-131 IU/L
Used to assess liver, biliary tract and bone disease
Aspartate Aminotransferase
10-40 units/L
released from injured hepatocytes
Alanine aminotransferase
10-40 units/L
released from injured hepatocytes
Gamma-glutamyl transpeptidase
9-58 units/L
Used to assess liver, biliary tract and pancrease
Bilirubin, total
0.1-1.2 mg/dL
used with other tests to determine causes of liver damage ans detect bile duct blockage.
Ammonia
19-60 mcg/dL
Though not diagnostic, often measured in suspected hepatic encephalopathy
Increase due to valproic acid, topiramate
Decrease due to lactulose
Amylase
60-180 units/L
Increase in pancreatitis, which can be caused by didanosine, stavudine, GLP-1 agoinst, DPP-4 inhibitors, valproic acid, hypertriglyceridemia
Lipase
5-160 units/L
Increase in pancreatitis, which can be caused by didanosine, stavudine, GLP-1 agoinst, DPP-4 inhibitors, valproic acid, hypertriglyceridemia
Creatine Kinase or Creatine Phosphokinase
Males: 55-170 IU/L
Females: 30-135 IU/L
Used to assess muscle inflammation (myositis), or more serious muscle damage, and to diagnose cardiac conditions
Increase due to daptomycin, statins, fibrates, emtircitabine, tenofovir, tipranavir, raltegravir, dolutegravir
CK-MB Isoenzymes
</= 6.0 ng/mL
Troponin T
0-0.1ng/mL (assay dependent)
Troponin I
0-0.5ng/mL (assay dependent)
B-Type natriuretic peptide
< 100 pg/mL or ng/L
N-terminal-proBNP
Males: < 61 pg/mL
Females: 12-151 pg/mL
Total Cholesterol
< 200 mg/dL
Low density lipoprotein
< 100 mg/dL, desirable
High density protein
> 60 mg/dL desirable
Non-HDL
< 130 mg/dL
Triglycerides
< 150 mg/dL
C-reactive protein
0-0.5 mg/dL
increase CRP indicates inflammation, which could be due to (infection, trauma, malignancy)
Fasting Plasma Glucose
> 126 mg/dL is positive for diabetes
100-125 mg/dL is positive for prediabetes
fasting> 8 hours prior
Hemoglobin A1C
< 7% (ADA)
</= 6.5% (AACE)
C-peptide (fasting)
0.78-1.89 ng/mL
decreased or absent in type 1
Urinary Albumin excretion
< 30 mg / 24 hours
Thyroid Stimulatng hormone
0.3-3 mIU/L
Increase TSH = hypothyroidism, decreased TSH= hyperthyroidism
increase or decrease due to amiodarone, interferons
Increase due to tyrosine kinase inhibitors, lithium, carbamazepine
Uric Acid
Males: 3.5-7.2 mg/dL
Females: 2-6.5 mg/dL
increase due to diuretics, niacin, low doses or aspirin, pyrazinamide, cyclosporine, select pancreatic enzyme products, select chemotherapy (due to tumor lysis syndrome)
Rheumatoid factor
negative, or </= upper limit of normal for the lab (usually < 20 IU/mL)
Erythrocyte Sedimentation Rate
Males: < 20 mm/hr
Females: < 30 mm/hr
Antinuclear Antibodies
Negative (titers may be provided)
CD4 T lymphocyte count
immunocompromised state: < 200 cells/mm3
CD4 count is an inducator of immune function and helps establish the need for opportunistic infection prophylaxis
HIV RNA concentration (viral load)
undetectable
measured in copies/mL
pH (arterial)
7.35-7.45
pCO2 (arterial)
35-45 mmHg
pO2
80-100 mmHg
HCO3
22-26 mEq/L
O2 sat
> 95%
Prostate- specific antigen
< 4 ng/mL
can increase with testosterone supplementation
Used in detecting prostate cancer and BPH
Human Chorionic Gonadotropin
Varies by test
A positive result from blood or urine test indicates pregnancy
Lutenizing hormone
Varies during cycle
Rises mid cycle, causing egg release from the ovaries
Testing in urine with ovulation predictor kits for women attempting pregnancy
Lactic Acid
0.5-2.2 mEq/L
Lactic acidosis indicates anaerobic metabolism, which occurs in long distance running and in certain medicatl conditions
Increase due to NRTIs, metformin (low risk/ mostly with renal disease and heart failure), alcohol use, cyanide
Purified Protein Derivative or Tuberculin Skin test
No induration; induration is measured to assess exposure to Mycobacterium tuberculosis
Response is measureed by diameter of induration 24-48 hours
Interferon-Gamma Release Assay
Negative (for exposure to Mycobacterium tuberculosis)
Preferred test for most patients
Rapid Plasma Reagin or Venereal Diseases Reseach Laboratory
Negative
Non-treponemal antibody tests used to screen for syphilis. If the RPR or VDR is positive, confirmatory testing with a treponemal assay is performed. Titers may be reported and are used to monitor response to therapy
Thiopurine Methyltranferase
> = 15 units/mL
Those with a genetic deficiency of TPMT are at increased risk for myelosuppression and may require lower doses of azathioprine and mercaptopurine
Vitamin D, serum 25(OH)
> 30 ng/mL
decreased levels increase risk of osteoporosis, osteomalacia (rickets), CVD, diabetes, hypertension, infectious diseases and other conditions
