Lab Values Flashcards
What are the four groups of lab values?
- Biochemistry
- Haematology
- Urinalysis
- Arterial Blood Gas
Why is chem 7 performed and what does it measure?
-Evaluates kidney function, acid/base balance, blood sugar levels
- BUN: 7 to 20 mg/dL
- CO2 (carbon dioxide): 20 to 29 mmol/L
- Creatinine: 0.8 to 1.4 mg/dL
- Glucose: 64 to 128 mg/dL
- Serum chloride: 101 to 111 mmol/L
- Serum potassium: 3.7 to 5.2 mEq/L
- Serum sodium: 136 to 144 mEq/L
Functions of sodium?
- normal range: 136-145 mEq/L
- main cation
- helps transmit nerve impulses
- maintains acid/base balance
- osmotic pressure balance
- fluid balance
What is hyponatremia?
-loss of Na+ or ↑H2O in body
common causes:
- excessive H2O intake
- Na+ depletion
- loss of Na+ through urine
- vomiting/diarrhea
- gastric suctioning
What is hypernatremia?
-loss of fluids or excess NaCl intake
common causes:
- dehydration
- overuse of IV NS solution
- impaired renal function
Chloride functions?
- main anion in ECF
- normal range: 98-107 mmol/L
- maintains osmotic pressure
- water balance
- acid base balance
What is hypochloremia?
-↓d Cl- intake, ↓d absorption or ↑d Cl- losses
common causes:
- vomiting
- gastric suction
- diarrhea
- diuretic use
** Decrease in cl- = increase in Na
What is hyperchloremia?
-↑d Cl- intake, ↑d absorption or Cl- retention
common causes:
- ↑d NaCl intake
- dehydration
- renal failure
- use of certain drugs
**Increase in cl- + decrease in Na
Potassium functions?
- main cation in ICF
- normal = 3.5–5 mmol/L
- cardiac/skeletal muscle contractions
- transmit nerve impulses
- maintain cell electrical neutrality/osmolarity
*changes in K+ can affect neuromuscular and cardiac functioning
What is Hypokalemia?
-loss of or poor intake of K+
common causes:
- diuretics
- inadequate K+ intake
- large does of corticosteroids
- aftermath of tissue destruction or high stress
- associated with metabolic alkalosis
What is Hyperkalemia?
-↓ K+ excretion or high intake
common causes:
- renal failure
- too-rapid IV KCl infusion
- initial reaction to massive tissue damage
- associated with metabolic acidosis
Bicarbonate (HCO3-) functions?
anion in blood
normal = 22-29 mmol/L or mEq/L
-maintains acid/base & electrolyte balance
Base Deficit results in?
-Metabolic Acidosis: due to loss of HCO3-, ↑d Cl-, or ↑d production of acids common causes: renal failure severe dehydration diabetic acidosis
-Resp Alkalosis:
compensating for low PaCO2
Base excess results in?
-Metabolic Alkalosis: due to loss of H+, low K+, or low Cl- common causes: loss of gastric contents ↑d intake of HCO3-
-Resp Acidosis:
compensating for high PaCO2 in pt with chronic lung disease
Magnesium (Mg2+) functions?
- main cation in ICF after K+
- normal = 1.8-3.0 mg/dL or 0.8-1.2 mmol/L
- promote enzyme reaction in cell during carbohydrate metabolism
- DNA and protein synthesis
- Influence vasodilaiton and irritability/contractibility of cardiac muscles
- helps Na/K cross cell membrane
- mainly excreted by kidneys
What is hypomagnesium?
-chronic problem with ↓d Mg2+ intake over time
common causes:
- chronic malnutrition
- diarrhea
- diuretics
- diabetes
- refeeding syndrome
What is hypermagnesium?
↑d Mg2+ intake
common causes:
- renal failure
- IV MgSO4
Functions of glucose?
Levels influenced by?
- energy source for most cells of body
- levels influenced by insulin,glucagon, carb intake
-Fasting Plasma Glucose
normal = 70-99 mg/dL
What is hypoglycemia?
-in diabetics:
too much insulin or too high dose of po antidiabetic agents
too little food
↑d exercise without additional food intake
-in pregnancy:
during first 3 mos
during labour
What is hyperglycemia?
-most common cause = Diabetes Mellitus (persistently high)
other possible causes: -glucocorticoids stress (epinephrine) conditions that cause abn pituitary gland functioning ⇒ secretion of growth hormone pregnancy
What is creatinine?
-by-product of muscle contraction
normal:
men: 0.6-1.5 mg/dL
women: 0.6-1.1 mg/dL
- excreted by
decreased: may indicate muscle tissue atrophy
increased: renal damage
What is urea nitrogen (BUN)
-Waste product of urea which is formed in the liver
normal = 8-25 mg/dL
- decreased: overhydration, ↑ADH, liver failure
- increased: diseased/damaged kidneys, decreased renal perfusion, severe dehydration, diet high in protein
Liver enzymes?
- alkaline phosphatase (alk phos/ALP)
- found in tissues of liver, bone, intestine, kidneys, & placenta
-alk phos found in liver excreted in bile
normal:
Men: 45-115 U/L
Women: 30-100 U/L
alanine aminotransferase (ALT)
aspartate aminotransferase (AST)
largest concentrations found in liver tissue
ALT normal:
Men: 10-55 U/L Women: 7-30 U/L
AST normal:
Men: 10-40 U/L Women: 9-25 U/L
Decreased ALP (liver enzyme)?
- in adults: scurvy (very low level), malnutrition, excessive vitamin D intake
- in pre-pubescent child: lack of normal bone formation, genetic defect
Increased ALP (liver enzyme)?
- during pregnancy
- in infants & children
- in non-pregnant adult, indicates bone or liver abnormality
common causes:
- Paget’s disease
- metastatic CA to bone
- liver dysfunction
ALT (liver enzyme)?
- decreased: unlikely
- elevated: indicates possible liver tissue necrosis or liver damage from drugs
common causes:
- severe hepatitis
- infectious mononucleosis
other possible causes:
-shock, Reye’s syndrome, CHF, preeclampsia
AST (liver enzyme)?
- decreased: unlikely
- increased: indicates possible liver necrosis
-common cause:
hepatitis
-other possible causes:
shock, trauma, cirrhosis, Reye’s syndrome, pulmonary infarction
Bilirubin?
-normal (adult): bili uncongugated (BU) or indirect = 0.1-1.0 mg/dL bili conjugated (BC) or direct = 0.0-0.4 mg/dL
Total bili = 0.1-1.0 mg/dL
increase or decrease of bilirubin?
-decreased: not of concern
BU
-increased: 2 possibilities
1. increased RBC hemolysis
-common causes: Sickle cell disease autoimmune disease hemorrhage drug toxicity transfusion reaction Rh or ABO incompatibility in infant
- liver dysfuntion
-common causes:
cirrhosis
hepatitis
BC
increased: indicates obstruction of bile ducts
common causes: gallstones, tumour, scarring of bile ducts
Amylase?
digestive enzyme: breaks down starch found in liver & pancreas
-decreased: kidney disease & pregnancy toxemia (pre-eclampsia)
-increased: indicates presence of condition affecting pancreas
common cause: pancreatitis
Lipase?
digestive enzyme: metabolized by dietary fats
decreased: cystic fibrosis
increased: indicates presence of condition affecting pancreas
common causes: pancreatitis, pancreatitic duct obstruction, pancreatic CA
Hameatology
routine = Complete Blood Count (CBC) components: Hematocrit (Hct) Red Blood Cells (RBC) Hemoglobin (Hgb) leukocyte or White Blood Cells (WBC) Platelet count Mean corpuscular volume (MCV) Mean corpuscular Hemoglobin (MCH) Mean corpuscular hemoglobin concentration (MCHC)
Hematocrit (Hct)
useful if dehydration status of pt is normal
aka packed cell volume % of RBCs in plasma normal: men: 37-49% women: 36-46%
Decreased hematocrit?
- due to increase plasma volume or ↓ in RBCs
- common cause = massive blood loss
Increased hematocrit?
- due to any decrease in plasma volume
- common cause = dehydration
RBC?
count of no. of RBCs per cubic mm (mm3) normal: men: 4.5-5.3 x 106/mm3 women: 4.1-5.1 x 106/mm3 erythropoietin stimulates production of RBCs
Decreased RBC?
can be due to: abnormal erythrocyte loss abnormal erythrocyte destruction lack of essential elements/hormones for erythrocyte production bone marrow suppression
Increased RBC?
Polycythemia or Erthrocytosis
physiologic: move to high altitude or post ↑d physical training
primary: polycythemia vera
secondary: state of chronic hypoxia
*increase could be from COPD, would result in hypoxemia
Hemoglobin (Hgb)?
component of RBC normal: men: 13.0-18.0 g/100 mL women: 12.0-16.0 g/100 mL needed as part of assessment for anemia
Decreased Hgb?
any condition that causes ↓ in RBC leads to ↓ in Hgb
-common causes:
blood loss
hemolytic anemia
bone marrow suppression
Increased Hgb?
rare
WBC?
-produced in: bone marrow and some mature lymph node
normal: 4 500 – 11 000/mm3
function:
helps to fight infection
What is the cause of leukopenia?
bone marrow deficiency or failure
certain medications
disease of liver or spleen
radiation therapy or exposure
What is the cause of leukocytosis?
infection inflammatory disease anemia bone marrow tumors leukemia
Function of platelets?
- prevent bleeding
- formed by bone marrow
- removed by spleen
- normal: 150 000 – 4500 000/mm3
What is Thrombocytopenia? causes?
-idiopathic thrombocytopenic purpura=unknown cause of bruising
post viral infections, AIDS
systemic lupus erythematosus
some types of anemia or other hemolytic disorders
chemotherapeutic drugs or radiation
heparin
overactive or enlarged spleen
post autotransfusion or any type of extracorporeal bypass
What are some causes of thrombocytosis?
malignant tumours or metastatic lesions
polycythemia vera
splenectomy
What is PTT? (partial thromboplastin time)
- detects presence of bleeding disorders, monitors effectiveness of heparin therapy
range: normal: 22.1-34.1 s
Decreased PTT?
- not clinically significant
- normal in pregnancy
Increased PTT?
bleeding disorder
common = hemophilia (hereditary disorder)
Heparin therapy levels for PTT?
- control: 25-37 s
- therapeutic: 1.5-2.3 times control
What is PT/INR?
- Prothrombin Time
- prothrombin/factor II: protein produced in liver
- International Normalized Ratio: comparison of animal thromboplastin to human source of thromboplastin
Decreased PT/INR?
not clinically significant
Increased PT/INR?
common:
advanced liver cirrhosis
bile duct obstruction
PT/INR levels for Oral Anticoagulant Therapy?
- control PT: 12-15 s
- control INR: 1.0
- therapeutic INR: 2.0-3.0
What is Hemoglobin A1C?
-Hgb A1 = glycosylated part of Hgb monitors control of glucose level for past 2 – 3 months reference values: 4-5.6% without diabetes 5.7% prediabetes 6.5% diabetes
What is urinalysis?
screening test of urine
result(s) may indicate need for further assessment
-colour:
normal: light yellow to dark amber
changes may be due to concentration, meds, foods, infection
Character of Ua?
-normal: clear
changes may be due to presence of purulent matter, blood, bilirubin or protein
Ph values for Ua?
-normal: 4.5-8.0
changes with food & metabolic state
lower (acidic): diet that includes meat & eggs
higher (alkaline): meatless diet, UTI
what are specific gravity values?
- part of fluid balance assessment
normal: 1.015-1.025
decreased: over hydration, diuretics
increased: dehydration, ↑d secretion of ADH
glucose in Ua?
-normal: negative
increased (glycosuria): hyperglycemia, ↓d renal threshold for glucose (present if it passes body’s threshold)
ketones in urine?
-normal: negative
due to ↓d availability of glucose
causes: diabetes, starvation, vomiting, fasting or all protein diet
Protein in urine?
- normal: negative to trace
causes: diabetes, renal dysfunction
*don’t test for protein if pt is stressed or there is a UTI infection present
Nitrites in urine?
-normal: negative
presence may indicate UTI, but not always
Leukocyte Esterase in urine?
normal: negative
presence may indicate UTI
Leukocutes + nitrites in urine indicate what?
presence of UTI
Blood gas?
-purpose: to monitor resp status or acid-base balance
-normals: pH =7.35-7.45 PaCO2 = 35-45 mmHg PaO2 = 80-100 mmHg HCO3 = 22-25 mEq/L
Ph values of blood gas?
is it 7.45?
then, alkalotic
partial pressure of carbon dioxide values for blood gas?
look at PaCO2 :
is it abnormal?
if not, then go to step 3
if yes, did it go up or down?
if it went up or down, did pH seesaw with it?
if yes, then resp problem.
Bicarbonate values for blood gas?
look at HCO3-:
is it abnormal?
if not, then not metabolic problem.
if yes, did it go up or down?
if it went up or down, did pH take same elevator?
if yes, then metabolic problem.
if no, then metabolic function compensating for resp problem.
Partial pressure of 02 values for blood gas?
PaO2 interpreted directly
PaO2 70 to 80 mmHg = mild hypoxemia
PaO2 60 to 70 mmHg = moderate hypoxemia
PaO2 less than 60 mmHg = severe hypoxemia
