Common Lab Tests Flashcards
Basic Urinalysis (dipstick)
basic urinalysis can give/tell you info about:
- color
- specific gravity
- pH
- heme/blood
- albumin/protein
- urinary glucose
- ketones
- nitrite
- leukocyte esterase
- bilirubin
- urobilinogen
Urine Color: Normal
pale yellow (straw) to amber (in between)
Urine Color: Straw
normal but low specific gravity (ex: hydrated)
Urine Color: Amber
normal but high specific gravity (ex: dehydrated)
Urine Color: Colorless
common meaning:
- large fluid intake
- untreated DM
- diabetes insipidus
- alcohol
other:
- reduction of perspiration
- chronic interstitial nephritis
- nervousness
Urine Color: Orange
common meaning:
- dehydration/restricted fluid intake
- concentrated urine
- fever
-medications (Pyridium/AZO)
other:
- excess sweating
- small quantity of bile
- medications (sulfasalazine (GI))
Urine Color: Bright Yellow (neon)
result of B vitamin intake
Urine Color: Brownish/Greenish Yellow
result of bilirubin increase in urine
Urine Color: Reddish/Dark Brown
due to:
- blood
- hemoglobin
- myoglobin
- porphyria (metabolic dz)
- meds: cascara/Senna (laxative)
- foods: beets, blackberries, rhubarb
Urine Color: Milky
due to fat, pus, or WBC
Urine Color: Purple
due to:
- porphyria
- Purple Urine Bag Syndrome (Cath + infection)
Urine Color: Green
due to:
-medications
-food dye
Urine Color: Brown-Black
due to:
- hemoglobin
-Lysol poisoning
-Melanin
Urine Color: Black
due to:
- Alkaptonuria (metabolic disease)
Normal Urine Specific Gravity (SG)
1.0003-1.035
Concentrated Urine SG
1.025-1.030+
Diluted Urine SG
1.001-1.010
Infants (<2) Urine SG
1.001-1.018
High Specific Gravity
clinical implications:
- dehydration**
- DM
- fever
- vomiting
- diarrhea
- increase in ADH (antidiuretic hormone)
Low Specific Gravity
clinical implications:
- diabetes insipidus**
- decrease in antidiuretic hormone (ADH)
- glomerulonephritis
- severe renal damage
Urine pH
Average Range: 4.6-8 (6.0)
- low pH: acidic
- high pH: basic/alkaline
Acidic Urine Implications
- uncontrolled DM (ketoacidosis)
- some kidney stones
- emphysema
- diarrhea
- starvation
- dehydration
- diet high in protein
Alkaline Urine Implications
- UTI (some bacterial strains)**
- aspirin intoxication
- kidney problems
- diet high in fruits and veggies
Fruity Urine Odor
DM (ketosis)
Foul Urine Odor
bacteria
Other Urine Odors
can indicate metabolic diseases
- ex: maple syrup urine disease
Hematuria
blood in urine
- normal value in urine is NONE
- can be found through UA (dipstick) and microscope testing
False Positive for Hematuria
- menstrual blood
- concentrated urine
- vigorous exercise
False Negative for Hematuria
vitamin C
Clinical Implications of + Blood in UA
COMMON:
- lower UTI**
- nephrolithiasis**
- urinary tract cancers**
- renal cancers**
- urinary catheter (trauma)**
- anticoagulants**
- strenuous exercise**
Other:
- Hemophilia
- Lupus
- Glomerulonephritis
- Heavy Smokers
Proteinuria
increased protein in urine
**the presence of protein in urine is the single most important indication of renal (kidney) disease, even in a very healthy person, if persistent
- can be mild, moderate, or severe
Clinical Implications of Proteinuria
- various kidney diseases (DM)**
- chronic urinary tract obstruction
- malignant hypertension
- fever
-trauma - Lupus (can affect kidneys)
- poisoning
False Positive for Proteinuria
numerous WBCs/epithelial cells in sample
Glucosuria/Glycosuria
increased urinary glucose
- normal value of glucose in urine is NONE
Clinical Implications of Glucosuria
- DM** (+ glucose urine test = evaluation for DM)
- pituitary diseases/brain injury
- various kidney diseases
**+ glucose is NOT always abnormal: - could be due to a large meal OR emotional stress
False Negatives with Glucosuria
- increased Vitamin C in diet
- high presence of ketones
Ketonuria
increased presence of urinary ketones in urine
- normal value us NONE
Clinical Implications of Ketonuria
- DM (ketoacidosis)**
- starvation/fasting**
- high fat diets (keto)
- low carb diet
- prolonged vomiting
- fever
-anorexia - pregnancy/lactation
False Positives of Ketonuria
- dehydration**
- medications
Nitrites in Urine
some bacteria convert nitrate into nitrite, so nitrites in urine often indicate infection
- normal value of nitrite is NONE
Nitrite Accuracy in Infection
nitrites in the urine can come back negative during an infection if:
- patient is urinating frequently
- infection w/organisms that do not change nitrate to nitrite
- diet low in nitrates
False Positives with Nitrites in urine
- Pyridium/AZO**
- contamination
False Negatives with Nitrites in Urine
vitamin C
Leukocyte Esterase (LE) in Urine
LE is an enzyme in WBC’s
- normal amount in urine should be negative
Clinical Implications of LE in urine
- UTI**
- sterile pyuria
**+ reading indicates pyuria and should be evaluated microscopically
False Positives w/LE in Urine
- vaginal discharge**
- trichomonas
- parasites
- contamination of sample**
False Negative w/LE in Urine
- pyridium/AZO**
- vitamin C
Urinary Bilirubin
Normal range for bilirubin in urine is: 0-0.02 mg/dL
Clinical Implications of Increased Bilirubin in Urine
THINK LIVER
- hepatitis
- infection or toxic agents
- obstructive biliary tract diseases
always investigate increase in this protein
Interfering Factors w/Bilirubin in Urine
- false positive: Pyridium/AZO
- false negative: Vitamin C
Urobilinogen in Urine
normal range: 0.1-1.0 mg/dL
Increased Urobilinogen in Urine
indicates:
- liver disease**
- hemolysis
Decreased Urobilinogen in Urine
indicates:
- biliary obstruction (ex: gallstones, pancreatic cancer)
- antibiotic therapy
Urine Test Specimen Handling
test within ONE HOUR or refrigerate specimen otherwise:
- glucose levels may drop
- ketones may dissipate
- color will deepen
- urinary sediment will deteriorate
- bacteria will multiple
- pH will become more alkaline/basic
- bilirubin and urobilinogen may be oxidized
Urine Microscopic Analysis Can…
Test for:
- bacteria
- WBCs
- RBCs
- crystals
- Casts (CASTS=KIDNEYS)**
-> red cell
-> white cell
-> others: fatty, hyaline, granular, renal tubular epithelial cell
Urine Microscopy: Bacteria
- 20 or more bacteria/HPF may indicate UTI
- if nitrite positive too, reliable indicator of infection
Urine Microscopy: WBCs
- usually indicates UTI or injury (5 or more per HPF)
causes: - UTI**
- stones**
- cancer**
- inflammation**
HPF
high power field (microscopy)
Interfering Factors w/WBCs in Urine
-vaginal discharge
-trichomonas
-parasites
-heavy mucous discharge
Urine Microscopy: RBCs
significant if 2 or more RBCs/HPF
indicates:
- UTI**
- renal cancer**
- bladder cancer**
- kidney stones**
Urine Microscopy: Epithelial Cells
presence of squamous epithelial cells indicates contamination of sample
Urine Microscopy: Red Blood Cell Casts
indicates hemorrhage and always pathologic
- Glomerulonephritis**
- Renal infarction
- Lupus
- Others
Urine Microscopy: White Bood Cell Casts
come from kidney tubules and indicate renal parenchymal disease…
…may indicate:
- pyelonephritis
- glomerulonephritis
- other kidney disease
Urine Microscopy: Crystals
crystals are microscopic and can indicate many things based on the type; stones are visible to the eye in comparison to crystals
Uric Acid
acidic urine, normal or indication of kidney stones
Oxalate
acidic urine, normal or indication of kidney stones
Phosphate
alkaline urine, normal or indication of kidney stones
Cystine
acidic urine, PATHOLOGIC!!
Complete Blood Count (CBC) Test
performed on whole blood in a lavender/purple tube, which contains EDTA (prevents blood from clotting)
can quantify:
- WBCs
- RBCs
- platelets
- hemoglobin
- hematocrit
Interfering Factors w/CBC Test
- physiologic stress can alter/influence results
- natural body rhythms can cause fluctuation
- dehydration/overhydration can alter values
- fasting is not necessary but fat-laden meals may alter some results
WBC Normal Range in Blood
4,000-11,000 per microliter
Leukocytes
term for WBCs as a whole
Leukocytosis
increased WBCs
- WBC count above 11,000 per microliter
- usually a result of increase in just one type of WBC
- often a result of acute infection (or inflammation)**
-> but can also be indication of hemorrhage, leukemia, trauma, etc.
Leukopenia
decreased WBCs
- WBC count below 4,000 per microliter
causes include:
- viral infections **
- some bacterial infections
- BAD infections (sepsis)**
- meds that suppress bone marrow
- bone marrow disorders (leukemia)
5 Different WBCs
- Neutrophils
- Lymphocytes
- Eosinophils
- Monocytes
- Basophils
How High WBC Count Depends On:
- severity of infection
- patient’s age
- bone marrow efficiency/immune system
Neutrophils
most numerous WBC** and primary defense against microbial invasion
- are PMNs (polymorphonuclear neutrophils)
Neutrophilia
increased neutrophils in blood
pathologic causes:
- bacterial infection**
- inflammation**
- hemorrhage
- tissue damage
- leukemia
- heart attack (MI)
non-pathologic causes:
- stress/exercise
- steroids (prednisone)**
- exposure to temperature extremes
Neutropenia
decreased neutrophils in blood
causes:
- overwhelming bacterial infection (sepsis)**
- viral infection**
- drugs (ex: chemo)
- blood diseases (ex: leukemia)
also know: some elderly patients can have lower neutrophil counts in general
Lymphocytes
type of WBC that is a part of immune system
- made in bone marrow and plays role in immune response
- migrates to areas of inflammation
3 Types:
1. B Cells
2. T Cells
3. Natural Killer (NK) Cells
Lymphocytosis
increase in lymphocytes in blood
causes:
- infections
- mononucleosis (viral infection)**
- measles
- mumps
-varicella
- types of leukemia
- lymphoma
Lymphopenia
decrease in lymphocytes
causes:
- chemo and radiation**
- AIDS**
- bone marrow disorders
- heart failure
- renal failure
Eosinophils
type of WBC that fights disease and contains granules
- bilobed nuclei (also a PMN)
- chemicals in granules are toxic to invaders AND host cells
What can affect eosinophil count?
- time of day (low in morning, rises after noon)
- burns
- post-surgery
Eosinophilia
increased eosinophils in blood
causes:
- allergies
- asthma
- parasitic/tapeworm diseases
- medications
- some skin problems (eczema)
“Wheezes, sneezes, and weird diseases”
Eosinopenia
decreased eosinophils in blood
causes:
- medications
- early bacterial infection
Basophils
type of WBC that works w/immune system to defend body from allergens, pathogens, and parasites
- have granules that obscure the nucleus
- granules produce histamine and other substances
- are PMNs
- usually not seen in blood at all
Basophilia
increased basophils in blood
causes:
- inflammation like: allergies**, bowel diseases
- bone marrow problems: leukemia/lymphoma
- some infections (ex: varicella/chicken pox)
Basopenia
decreased basophil levels detectable
causes:
- acute phase of infection
- following prolonged steroid therapy
Monocytes
type of WBC that resides in blood to find and destroy germs and eliminate infected cells
- big cells w/big nuclei
- second line of defense against infection
Monocytosis
increased monocytes in blood
causes:
- infections (TB, parasites, ticks, etc.) and recovery**
- bone marrow/blood cancers
- some GI disorders (w/inflammation in intestines)
Monocytopenia
decreased monocytes in blood
causes:
- prednisone treatment
- HIV infection
Red Blood Cells (RBCs)
the most abundant blood cell in the bloodstream
- do not have nuclei
- carry oxygen to tissue and bring back CO2 to lungs (uses hemoglobin to do this)
- lifespan: ~120 days
Normal Range for Red Blood Cells
Men: 4.6-6 x 10^6/mL
Women: 4.0-5.0 x 10^6/mL
Erythrocytosis
Increased RBC count
causes:
- polycythemia vera**
- renal disease
- high altitude
- pulmonary disease
- cardiovascular disease
- tobacco use
- dehydration
Erythrocytopenia
decreased RBC count
causes:
- anemia**
- bone marrow/blood cancers
- Lupus
Hemoglobin (Hgb)
part of RBC that carries oxygen and CO2
- the initial test to check for anemia
Normal Range for Hemoglobin
Female: 12.0-15.5 g/dL
Male: 13.6-17.5 g/dL
Panic values: <7
Hematocrit (Hct)
the % of RBCs within the entire blood
- depends on number and size of RBCs
Normal Range for Hct
Female: 35-45%
Male: 40-50%
Hematocrit & Hemoglobin Calculation
Hct is approx 3x the Hgb
Hct = Hgb x 3
Platelets
smallest of the formed cellular elements and mostly formed in bone marrow (some in spleen)
- play important role in blood clotting**, vasoconstriction, etc.
Normal Range for Platelets
approx 150,000-450,000/mL
Thrombocytosis
increased platelets in the blood
causes:
- cancer (leukemia)**
- trauma and exercise
- acute infections**
- iron deficiency anemia
Thrombocytopenia
decreased platelets in blood
causes:
- some infections (viruses, bacteria, ticks)**
- ITP (idiopathic thrombocytopenia)
- other anemias
- liver disease (cirrhosis)**
Basic Metabolic Panel (BMP)
gets levels for:
- Na+
- K+
- Cl-
- HCO3-
- BUN (Blood urea nitrogen)
- Creatinine
- Serum Glucose (“blood sugar”)
- Ca2+
BMP is performed on serum or plasma
- serum: gold tube that has gel that helps serum separate from other blood components
- plasma: light green tube w/heparin (anticoagulant) in it
BMP Sodium (Na+)
sodium is the primary cation in extracellular fluid (outside cell)**
- normal range: 134-145 mEq/L
Hypernatremia
increased serum Na+
- indicates a total water deficit in the body
Hyponatremia
decreased serum Na+
- indicates a total water excess in the body
BMP Potassium (K+)
potassium is the primary cation of intracellular fluid (inside cell)**
- changes in K+ can affect nerves, muscles, and the heart**
- if blood sample gets hemolyzed during collection, K+ leaves the cells and leads to a. falsely elevated K+ level
Hyperkalemia
increased K+ in blood serum
Hypokalemia
decreased K+ in blood serum
BMP Chloride (Cl-)
chloride is the primary anion of the extracellular fluid
- typically goes hand-in-hand w/Na+
Hypercholeremia
increased chloride in blood serum
Hypocholeremia
decreased chloride in blood serum
- ex: increased sweating
BMP Bicarbonate (HCO3-)
ion formed in kidneys that acts as a buffer when H+ is produced by metabolism of acids
- normal range: 22-26 mEq/L
- holds CO2 content
Alkalosis
increased bicarbonate in blood serum
Acidosis
decreased bicarbonate in blood serum
BMP Blood Urea Nitrogen (BUN)
protein metabolism leads to ammonia production and then urea is synthesized in the liver
- normal range: 10-20 mg/dL
Increased BUN Levels Indicates
- kidney insufficiency**
- urinary tract obstruction**
- dehydration
- increased protein ingestion
Decreased BUN Levels Indicates
- low protein diet**
- starvation
- cirrhosis
BMP Creatinine
muscles metabolize creatine, which leads to creatinine production
- more muscle mass = more creatinine production
- normal range: <1.5 mg/dL but with some difference in range between men and women**
Elevated Creatinine Indicates
decreased renal function**
Decreased Creatinine Indicates
decreased muscle mass/cachexia
Interfering Factors w/Creatinine Readings
- Vit C/Cephalosporin can cause falsely elevated levels
- A diet high in meat can cause an increased level
- May be falsely decreased by bilirubin or high levels of glucoseBMP
BMP Report - GFR
BMP results typically include a calculation of the GFR (glomerular filtration rate)
- indicates how well kidneys are working
- indicates how much blood is passing through glomeruli each minute
- calculation of GFR involves Scr, age, and sex
Glomerular Filtration Rate (GFR)
rate at which blood is filtered each minute
BMP Report - Anion Gap (AG)
BMP results typically include an anion gap (AG)
- formula: Anion Gap = Na - (Cl+HCO3)
- increased anion gap indicates type of acidosis
- decreased anion gap is very rare
Anion Gap (AG)
difference between serum cations and anions
formula: Anion Gap = Na - (Cl + HCO3)
BMP - Serum Glucose
glucose is a primary energy source for metabolism
- liver converts carbs to glucose
- excess glucose converted to glycogen in liver/muscle
- process needs insulin
- normal range of glucose in blood: 75-110 micrograms/dL
Hyperglycemia
increased serum glucose
causes:
- diabetes**
- endocrine disorders
- severe infection**
- steroids**
Hypoglycemia
decreased serum glucose
causes:
- endocrine disorders
- metabolic disorders
- meds (too much insulin)
- liver disease
BMP Calcium (Ca2+)
normal range: 9.0-10.5 mg/dL
Hypercalcemia
increased blood serum calcium
causes:
- heart problems**
- hyperparathyroidism (bone breakdown)**
- too much vitamin D**
- kidneys aren’t excreting Ca
Hypocalcemia
decreased blood serum calcium
causes:
- muscle contractions**
- seizure**
- hypoparathyroidism**
- vitamin D deficiency**
- renal insufficiency**
Hemoglobin A1c (Hgb A1c) Test
test that tells us the average blood sugar level of the past 6-12 weeks (avg lifespan of RBC)
- normal range: 3.8-6.4%
- elevated A1c of 6.5+ or more is diagnostic of DM**
- not accurate during pregnancy**, renal failure, or blood loss
- Hgb related diseases can increase or decrease Hgb A1c
Serum Amylase Test
tests for a pancreatic enzyme
- enzyme normalizes faster than lipase
Increased Serum Amylase Indicates
- pancreatitis**
- pancreatic obstruction
- gallbladder inflammation
Decreased Serum Amylase Indicates
- pancreatic insufficiency**
- liver disease
Serum Lipase Test
tests for pancreatic enzyme Lipase
- Lipase stays elevated longer in pancreatitis than amylase
Increased Lipase in Serum Indicates
- pancreatitis**
- pancreatic cancer
- gallbladder inflammation
Serum Aspartate Aminotransferase (AST) Test
tests for a liver enzyme
- although enzyme is also located in heart, muscle, kidney and a few other organs
- gets released when tissues are injured
- normal range: 9-40 U/L
Increased AST Indicates:
- liver problems**
- heart attack (MI)
Serum Alanine Aminotransferase (ALT) Test
tests for a liver enzyme that is primarily in lover but has small amounts in. muscles and heart
- also gets released when tissues are injured
- normal range: 0-35 U/L
Increased ALT Indicates…
liver damage** (infections, meds, alcohol, cancer, etc)
Serum Alkaline Phosphatase
looks for liver enzyme alkaline phosphatase
- present in many types of cells not just liver (includes bone, biliary tract, intestines, placenta, kidney)
- gets released when cells are destroyed OR during growth periods
- normal range: 30-120 U/L
Increased Alkaline Phosphatase Indicates…
- liver problems**
- bone disorders
- biliary tract disorders
Decreased Alkaline Phosphatase Indicates…
- osteoporosis**
- some vitamin deficiencies
Serum Bilirubin
bilirubin is conjugated in the liver and excreted in bile
- can also come from breakdown of RBCs
Increased Bilirubin in Blood Indicates…
- increased breakdown of RBCs (hemolysis)
- certain liver and bile duct problems
Decreased Bilirubin in Blood Indicates…
some types of anemia
What is a CMP?
CMP = Comprehensive Metabolic Panel
tests for everyone on BMP plus:
- AST
- ALT
- Alk phos
- Bilirubin
- Total protein
- Albumin
Serum Gamma-Glutamyl Transferase (GGT) Test
tests for liver enzyme GGT
- also found in kidney, prostate, and spleen
- levels are higher in male patients
Increased GGT Indicates…
liver problems** (including alcoholism)
Point of Care Testing (POCT)
- relatively inexpensive tests
- performed at “Point of Care (at/near bedside)
- can be performed by non-lab personnel
- gets results faster than non-POCT (less delay in treatment)
- speed at the expense of accuracy
- may need to do further confirmatory testing later
Types of POC Tests
- fingerstick glucose test
- urine pregnancy test
- rapid strep test
- Hgb A1c
- POC troponin (for diagnosis of MI)
