Clin Lab 2: Lect 1-3 Flashcards
What are the three functions of the kidneys?
Excretion- selective clearance
Homeostasis- water/E+, A-/B+ balance
Endocrine- erythropoeitin, prostaglandin/thromboxanes, renin synthesis
How is glomerular filtration rate maintained?
Myogenic control related to degree of stretch on afferent arteriole
Stress induced inhibit filtration, constrict afferent
RAAS increases SBP
Tubular reabsorption begins when filtrate enters ? and involves ? two processes?
PCT
Near total reabsorption of organic nutrients
Hormonal reabsorption of water
Virtually all nutrients and lipids are reabsorbed where in the kidney?
PCT
Where is Mg reabsorbed?
Where is urea reabsorbed?
DLoH
PCT and CD
How do substances move from peri-tubular capillaries into tubular filtrate?
Active transport
What are the two functions tubular secretion completes?
Eliminates non-organics not found in blood
Acid-base regulation via secretion of H/NH4
Where does final urine concentration begin?
How is this process controlled?
Late DCT and CD
Regulated by ADH
What would be the effect if there was NO ADH in the body?
Low osmolality of ECF
Low number of aquaporins
Low water reabsorbed from CD
Large vol of diluted urine
What type of urine is excreted from a DM PT?
What type of urine is excreted from a DI PT?
Looks dilute, high osmolality
Truly dilute, low SpecGrav
When is Polyuria seen?
When is Oliguria seen?
When is Anuria seen?
DM/DI
Dehydration
Kidney damage, decreased blood flow
What five characteristics of a urine sample will change with time and why?
Color- darkens, RedOx of metabolites Odor- inc, urea->ammonia pH- inc, loss of CO2 Nitrite- inc number of nitrate reducing bacteria Bacteria- increased numbers
What are the three parts to urinalysis?
Physical exam
Chemical analysis
Microscopic exam
What gives urine the yellow color?
Urochrome
What causes urine to be dark amber/orange?
Presence of conjugated bilirubin
Photo-oxidation of urobilinogen to urobilin causes color change to yellow/orange
What causes pink/red/brown urine?
RBCs in an acidic urine x hrs= brown urine from Hgb oxidation to methemoglobin
Intact RBCs in a urine samples will give the sample a ___ appearance
What if Hbg/Mgb is present?
Hematuria- Cloudy
Specimen is red and clear
What causes urine samples to turn brown/black?
Methemoglobin: Standing-> Hbg Fe in acidic urine is oxidized to methemoglobin= brown urine
Melanin: neutral pH urine->black w/ melanin present
Define Homogentisic Acid and when is it seen
Inborn error of metabolism
Increased excretion occurs in alkaptonuria (metabolic defect) causing urine to appear brown if it’s more acidic
When/why would melanin be present in a urine sample turning it brown/black?
Metastatic malignant melanoma
What causes a urine sample to turn dark orange?
What causes urine to turn blue/green?
Pyridium from cystitis Rxs (Rifampicin)
UTI w/ Pseudomonas
Intestinal tract infection= inc urinary indican
What are the non-pathological reasons for hazy urine?
Amorphous crystals Squamous epithelial cells Seminal fluid Fecal contamination Mucus
What are the pathological reasons urine samples can be hazy?
R/WBCs
Bacteria
Renal epithelial cells
Lipids
What conditions can cause urine samples to smell more noxious/unusual?
Bacteria infection
Ketones- fruity
MSUD- syrup/burnt sugar
Foods- asparagus
Clinitests are often performed on Peds until what age and for what reason?
2y/o
Detect presence of: galactose, fructose, pentose or lactose
Glucosuria normally appears when the renal threshold of glucose exceeds what limit?
170 mg/dL
Glucosuria w/out hyperglycemia is related to ? caused by ?
Impaired tubular reabsorption
Pregnancy or heavy metal poisoning
What are the Renal-Associated reasons for a positive urine glucose result?
Fanconi Syndrome
Advanced Renal Dz
Osteomalacia
Pregnancy
Chemstrips can only test/detect what form of ketone?
Acetoacetic acid
Not acetone or hydroxybutyric acid
Acetoacetic acid is slowly and irreversibly decarboxylated into ? and excreted how?
Acetone
Skin, lungs, urine
Ketonuria can be caused by what issue?
Inability to utilize carbs (DM) forcing body to utilize FAs for fuel
What type of PTs/situations would a positive ketone result be seen?
DM Starvation High fat/protein, low carb diet Exercise Malabsorption Frequent vomiting
Explain Hemolytic Jaundice
Pre-Hepatic
Excessive RBC breakdown increasing bilirubin levels until overflow into intestines
What will bilirubin and urobilinogen levels be in a pre-hepatic issue PT urine sample?
Bilirubin- excretion rate maintained by liver
Urobilinogen- elevated in urine and blood
Explain Hepatic Jaundice
Damage/Dz to liver
Heme goes to liver but not enough blirubin is removed
Unconjugated bilirubin increases in the blood to kidney to urine
What will urobilinogen levels be in a Hepatic Jaunidce PT urine sample?
Normal or low
Define Bilirubinuria and what causes it
Increased conjugated bilirubin in urine due to hepatocellular disease/dec ability of liver to excrete all conjugated bilirubin into common bile duct
Bilirubinuria can be caused by what two issues?
Cirrhosis
Hepatitis
Explain Biliary Obstruction/Post Hepatic
Bilirubin can’t get to intestines, builds in blood and removed by kidneys
What will urobilinogen levels be in a Biliary Obstruction PT urine sample?
Little if any present
What are four reasons bilirubin wouldn’t be able to get into the intestines?
Carcinoma in liver or pancreas
Stones
Fibrosis
Where/how is urobilinogen formed?
Intestines by bacterial breakdown of conjugated bilirubin
What happens to a urobilinogen test if a urine sample is not delivered to the lab within the time frame/is not stored properly?
Urobilinogen will be rapidly oxidized into non-detectable urobilin
If urobilinogen is not/undetectable by a Chemstrip, what is the next sample needed for testing?
Stool
What are some prehepatic events that can lead to/cause increased urobilinogen in urine?
Increased Hgb breakdown
Hemolysis
Ineffective erthropoiesis
What are some hepatic events that can lead to/cause increased conjugated bilirubin in urine?
Hepatocellular disease from:
Hepatitis
Cirrhosis
What can cause a decreased to absent amount of urobilinogen in urine?
Intra / extra-hepatic obstruction
Carcinoma
Stones
Fibrosis
Define SpecGrav and what it indicates
Density of substance to reagent grade water
Indicates proportions of dissolved solids to total volume of specimen
What is the significance of a high specific gravity result?
Dehydration w/ oliguria
In DM Pts, a Solute Diuresis= urine w/ glucose and polyuria PT
What is the significance of a low specific gravity result?
Inability of tubules to concentrate
DI PT w/ polyuria and urine has low concentration
Define Isosthenuria
Consistent urine samples with SG of 1.010 which implies renal tubular damage and loss of function
What are the three most common causes of isosthenuria?
Chronic renal failure from:
Diabetic nephropathy
HTN Renal Dz
Chronic glomerulonephritis
Define Osmolality
Number of particles in a fluid sample
A more exact measurement of urine concentration than SpecGrav
What are the major clinical uses of osmolality include ?
DR FDC Dz Monitoring Response to ADH Fluid therapy DDx of Hyper/onatremia Concentration ability
Define ADH Neurogenic
Define ADH Nephrogenic
Neuro- DI from dec ADH production, concentration will occur after ADH injection
Neph- inability of tubules to respond to ADH, CD doesn’t have ADH receptors
Significance of positive blood results can mean one of what three things?
Intact RBCs
Free Hgb
Mgb
What are five causes of hematuria?
Glomerulonephritis Lower UTI Exercise Menstruation Renal calculi
What can cause hemoglobinuria?
Intravascular hemolysis
Exercise
May result from lysis of RBCs in UT, especially in dilute, alkaline urine
What causes Myoglobinuria?
How does it present?
Trauma/crush or Rhabdo
Normal appearing serum, elevated creatinine kinase and lactate dehydrogenase
Urinary pH may indicate what type of kidney issue?
Inability to secrete/absorb acid-base
What type of urine reduces/prevents calculi formation?
Alkaline
What serum protein is found in normal urine?
Albumin
Define Uromodulin
Tamm-Horsfall proteins- mucoprotein made in DCT and involved in cast formations
Chemstrips are most sensitive for detecting what protein in urine?
Albumin
Proteinuria is related to changes in what two things?
Glomerular blood flow
Enhanced glomerular permeability
What is pre-renal proteinuria associated with?
Non-renal Dzs causing increase in low weight plasma proteins (Hgb, Mgb) and acute reactants associated with infection/inflammation to pass through
PT with Multiple Myeloma will present with what changes to their urine samples?
Excess of Immunoglobulin light chains
What are causes of pre-renal proteinuria?
Multiple myeloma Renal artery stenosis HTN Fever Muscle injury
What causes renal proteinuria?
Kidney Dzs
Primary- glomerulonephritis, nephrotic syndrome
Induced- drug/toxin, systemic dz
What are three causes of tubular proteinuria (renal proteinuria)?
Defective tubular reabsorption characterized by increased levels of low weight proteins from:
Drug/toxin
Severe infection
Fanconi’s Syndrome
What are three causes of post-renal proteinuria?
Cystitis
Urethritis
Postatitis
What types of microbes can cause a nitrate change on Chemstrips?
E Coli
Proteus Sp
What type of urine sample is preferred for testing for nitrites?
First morning- allows for bacteria accumulation and longer conversion time of nitrate to nitrite
What can cause a false-positive urine nitrite results?
Positive nitrite result w/out UTI
Improper preservation of specimen causing increased E COli
Bacteria presence in urine specimen in significant numbers cn be due to infections in what two place?
Entire urinary system
Nephron to bladder
What is the significance of positive Leukocyte Esterase in urine samples?
Pyuria- inc WBCs due to infection/inflammation in GU system
Bacteria infections in UT generating a positive urine LE will often have what other positive test indicator?
Nitrite
A positive LE urine sampled will be microscopically examined and might be able to see what three things?
Yeast
Bacteria
Trichomonas
What part of a urine sample will be altered/changed the most by prolonged exposure to light?
Bilirubin
Dark urine samples are most likely due to what part of the sample?
Bilirubin
___ are more permeable to H2O and Na than other capillaries
Glomeruli
High blood osmolality triggers what to be released in the body?
ADH
SpecGrav is an index of the kidney’s abilities to do ? function
Concentrate urine
What urine sample is most appropriate for suspected pregnancy test?
First morning
Urine sample with elevated urobilinogen and negative bilirubin levels may indicate what issue?
Intravascular hemolysis
Microabluminuria, pre-eclampsia and orthostatic proteinuria are all examples of proteinuria coming from what part of the system?
Renal
Acute phase reactants and multiple myeloma are both conditions that cause proteinuria from where?
Pre-renal
Prostatits and vaginal inflammation are both causes of proteinuria from what part of the system?
Post-renal
What is the purpose of microscopic examination of urine sediment?
Detect and identify insoluble materials
What are insoluble materials that can be identified in urine?
MY B SCREW CAP Mucus Yeast Bacteria Sperm Casts RBC Epithelial WBC Crystals Artifacts Parasites
Define Aliquot
10mL of urine specimen centrifuged to concentrate insolubles at bottom of sample
RBCs in a urine sample are associated with ?
Glomerular damage
PTs bleeding into their urinary tract from the renal pelvis to urethra will have what type of urine sample?
No significant proteinuria
No other cell types
No casts
What are 5 examples of issues that can cause bleeding from renal pelvis to urethra and cause RBCs to be found in urine?
Stones
Neoplasms
Trauma
Prostatitis
Hematuria associated with a UTI will be associated with ?
Pyruia
Nephronal hematuria is seen with ? and ?
Proteinuria
RBC casts
Nephronal hematuria is seen with proteinuria and casts but is caused by ?
Glomerular disease
Tubular disease
What considerations need to be present when considering cause of RBCs in urine samples?
Exercise
Menstruation
Pyuria indicates the presence of ? or ? in GU system?
Infection
Inflammation
What three findings are more indicative of a kidney infection?
Mod/heavy proteinuria
WBC casts
Hematuria
How are lab results differentiated between a kidney infection and a bladder infection?
Bladder- hematuria, less proteins and no casts
What type of cell is most frequently seen but least relevant for clinical use in urine samples?
Squamous Epithelial cells
Squamous epithelial cells arise from where in the fe/male GU system?
Female- entire
Male- lower urethra
Large numbers of squamous epithelial cells in a sample is indicative of ?
Contamination
Where are transitional epithelial cells found within the GU system?
Renal pelvis lining
Ureters
Bladder
Upper male urethra
Finding transitional epithelial cells is only considered pathological if ?
No instrument procedure has been recently performed
What can cause renal tubular epithelial cells to be found in urine samples?
Heavy metals
Drugs
Hbg/Mgb toxicity
Pyelonephritis
Define Oval Fat Bodies and when are they seen
RTE cells containing lipids
Common in nephrotic syndrome
Where are casts primarily formed?
Lumen of DCT and CD
Origin site determines width
Casts are usually formed/found in what type of urine?
Concentrated acidic
What are the 3 major factors that enhance cast formation?
Proteinuria
Stasis
Tamm-Horsfall proteins
What type of cell is Tamm-Horsfall proteins and where are they made?
Mucoprotein
Renal tubular cells
What appearance do casts have?
Parallel sides and rounded edges
May be wrinkled/convoluted depending on age
Characteristics of Hyaline Casts
Almost entirely of Tamm-Horsfall proteins that are colorless w/ a refractive index close to urine
Non-pathological causes of hyaline cast formation?
FEED
Fever Exercise Emotional stress Dehydration
Pathological causes of hyaline cast formation?
Glomerulonephritis
Pyelonephritis
Chronic renal disease
The presence of ___ casts is indicative of serious renal disease
Cellular
RBC casts are primarily associated with damage to ?
Glomerulus (glomerularnephritis)
WBC casts are indicative of ?
Nephron infection/inflammation
Most frequently with pyelonephritis
How are WBC and RTE cell casts differentiated visually?
RTE- look for central round nucleus
RTE cell casts are indicative of ? and are usually seen with what other findings?
Renal tubular disease
Red and White cell casts
What are fatty casts associated with?
Renal diseases
Particularly- nephrotic syndrome
Possible- toxic tubular necrosis, DM
What are non-pathogenic granular casts indicative of?
By product of protein metabolism excreted by tubule cells and can be seen in normal/healthy PTs
What are pathological granule casts associated with?
Any disorder causing cell cast formations
Degeneration of cell casts occurs as stasis worsens
Characteristics of waxy casts
Severe urine stasis in tubules
Frequently found in chronic renal failure
Characteristics of broad casts
Formed in diluted tubules with very severe stasis and referred to as renal failure/end stage failure casts
When are crystals formed in urine?
What types are formed in what types of urine?
Precipitation of urine salts subjected to pH/concentration changes
Amorphours urates- acidic
Amorphous phosphates- alkaline
Urine crystals may represent what types of disorders?
Liver Dz
Genetic defects
Renal damage from crystal deposits in tubular cells
Bacteria presence in urine is indicative a clean catch did not happen, but is usually reported when identified in fresh specimens if what else is seen in the sample?
WBCs
What organism is most commonly found in urine?
What cell is this commonly confused with?
Candida albicans
RBCs
What is the most frequently encountered parasite in urine?
What characteristic is required for ID?
Trichamonas vaginalis
Movement, immobility resembles WBCs
Intestinal parasites (adult or eggs) in urine samples are indicative of what?
Fecal contamination
Urine sample Chemstrips can have a false positive result for proteins if ? is in the urine?
Sperm
What insoluble finding in urine is not clinically relevant?
Starch granules- body power
First thing lab does to urine sample?
Look at color/clarity
Urine sample positive for nitrite and leukocyesterase indicates ?
UTI
Urine sample positive for glucose, ketones and has a low pH?
DM
Urine sample with bilirubin, but no urobilinogen means?
Post hepatic biliary obstruction
ALT/AST more indicative for ? organ?
Lipase is for ? organ?
Liver
Pancreas
Unconjugated bilirubin is __ soluble
Conjugatd bilirubin is __ soluble
Urobilinogen is _ soluble
Un- lipid
Con- water, added sugar
Lipid
Insulin is made in _ cells
Glucagon is made in _ cells
B
A
Define Glycogenesis
Define Glycolysis
Glucose from G6P
G6P to pyruvic/lactic acid
Hyperglycemia is what type of issue?
Hypoglycemia is what type?
Osmotic water loss
Cerebral problem
T1DM is called ?
T2DM is called ?
1= insulin dependent 2= Non-insulin dependent/insulin resistant
The AMA panel for DM management includes what tests?
LAAB Lipid profile A1C Anion Gap BMP
What is an early indicator of diabetes?
What lab result is typically only seen in T1DM?
What 3rd test may also be included?
Micro-ablumin
Ketone bodies
Fructosamine
Glycated Hgb is made from ___ + ____
Glucose
Schiff base
A1C levels indicate what time frame?
6-8wks
A1C is a lower diagnostic performance in what PT populations?
Pregnancy
Elderly
Non-Hispanic blacks
What are the functions of fructosamine and glycated albumin tests?
Monitoring tools to help diabetics control glucose levels
(diet/med adjustments evaluation)
NOT for diabetes Dx
Diabetic A1C, FPG and OGTT numbers?
+6.5
+126
+200
Prediabetic A1C, FPG and OGTT numbers?
5.7 - 6.4
100 - 125
140 - 199
Normal A1C, FPG and OGTT numbers?
5
99 or less
139 or less
How is serum fructosamine formed?
Non-enzymatic glycosylation of serum proteins (albumin makes up 80%)
Serum glycated albumin generally reflects state of glycemic control for what time frame?
Preceding 2-3wks
Other than shorter time frame monitoring, Fructosamine and Glycated Albumin are usefule for what PT population?
Disorders causing shortened RBC lifespan (hemolytic anemia, pregnancy)
What type of Hbg variant may affect A1C measuring methods?
HbSS
Fructosamine and glycated albumin results are both affected by what types of condition?
Anything that affects serum albumin production
Ketone bodies in T1DM PTs are a result of what two things?
These result in what types of ketones to build up?
Inc lipolysis, dec re-esterification of FA to triglycerides
Acetoacetate and B-hydroxybutyrate
Ketone lab tests usually use ___ methods like ? or ?
Semi-quantitative
Acetest or KetoDiastix
AceTest and KetoDiastix are only sensitive for what ketone?
Why is this importatn?
Acetoacetate
Neg test do not rule out ketoacidosis due to inc B-Hydroxy levels
Persistent proteinuria detectable by routine screening indiates ?
Overt diabetic neuropathy
What precedes the proteinuria diabetic nephropathy stage that is not detected by routine lab methods?
Inc urine albumin excretion
What lab results defines microalbuminuria?
What does this result NOT indicate?
Proteinuria >30 <300/24hrs or urine albumin excretion
Not0 smaller than normal size albumin
INcreased urine albumin excretion indicates an increase in ? and is a marker of ?
Transcapillary passage
Marker of micro-vascular dz
What are four causes of non-diabetic hyperglycemia?
CF diabetes
Corticosteroids/BBs
Multi-organ failure
Shock
What is the counter result of hyperglycemia?
Each 100mg increase in blood sugar decreases plasma sodium by 1.7 = dilutional hyponatremia
What are the six causes of hypoglycemia?
G HOME Hormone deficiency Overtreatment of insulin Malnutrition Excessive ETOH Glycogen strorage Dz
What other causes other than G HOME can cause hypoglycemia?
Islet cell hyperplasia
Insulinoma
What is the recommended cutoff for early detection of CKD in diabetics using the test for microalbumin?
> 30mg/24hrs
What is the ADA recommended cutoff value for adequate control of glucose as measured by glycated Hgb?
6.5%
BMP tests include ?
Ca CO2 Cl K Na
Creatinine
Glucose
BUN
What are the intra/extacellular cat/anions?
Cl- EC anion
K- IC cation
Na- EC cation
CLs funciton in the body?
Maintains acid-base balance
Facilitates O2/CO2 exchange in RBCs
Electrolytes have key roles in what four processes?
Water homeostasis
pH regulation
Heat, nerve and muscle function
RedOx reactions
What electrolyte is most important for water regulation and how is it regulated?
Na
Aldosterone- raises
ANP- lowers
What is an important initial step in assessment of hyponatremia?
Plasma osmolality
What are two causes of Hypo-osmotic hyponatremia normovolemic?
What is the pathalogy causing this?
Isolated NaCl deficit
Normal TBF
SIADH
Diuretics
Hypothyroid/aldrenalism
What causes hyperosmotic hyp0natremia?
Inc quantities of solutes in ECF from shift of water/ ICF shift of Na to maintain balance between ECF/ICF compartments
Define Isosmotic Hyponatremia
Dec plasma Na but,
plasma osmolality, glucose and urea are norm= pseudohyponatremia from electrolyte exclusion
(hyper protein/lipid emia)
How is K reulated?
Insulin and catecholamines- causes K movement into cells
What are the physiological roles of K?
Muscle repolarization
pH balance- acidosis= K into plasma, H into cell; alkalosis= k into cells
What are the two types of hypokalemia?
True deficit- renal or nonrenal loss based on K urinary excretion
Redistribution- from insulin, epi, alkalosis
What are the physiological roles of Cl?
Opposes Na, maintaines osmotic press/elec neutral
Moves passively with Na, inversely with BiCarb
Inc resting potential
Why do blood cells need to be separated from plasma prior to testing?
BiCarb -> CO2
Artificial inc of Cl to balance loss of BiCarb and dec of total CO2
3 causes of hypochloremia?
Hyponatremia
Vomiting
Inc BiCarb- Met Alk; Resp Acid
What are 4 causes of hyperchloremia?
Hypernatremia
DI
Dehydration
Met acid/Resp alk
What is BiCarb a measurment of?
Metabolic component of acid-base balance
How is Ca regulated?
What E+ is it’s inverse?
Calcitonin and PTH
PO4
What enzyme is a cofactor for enzymatic reactions?
Mg
Intracellular Cations x 2
Extracellular Anions x 2
Extracellular Cations x 1
Intra C- K Mg
Extra A- Cl BiCarb
Extra- Na
Elevated Anion Gap Metabolic Acidosis acronym?
MULEPAKS Methanol intox Uremia Lactic acidosis Ethylene glcyol intox Paraldehyde Intox Alcohol ketoacidosis Ketoacidosis Salicylate intox
DDx Non-Gap Acidosis
GI BiCarb loss- diarrhea
Renal BiCarb loss- CAIs, renal tube acidosis, aldosterone inhibitors, hypoaldosteronism
When water is lost but E+ are retained and osmolarity of ECF rises, osmosis will move water in what direction?
Out of ICF into ECT until isotonicity is reached
What E+ movement will not affect fluid levels in blood?
Cl shift
ABG measures what four things in blood?
Calculated: pH, PCO2, HCO3
Estimated: PO2
What happens to Co2 and BiCarb when blood pH increases?
Alkaline= dec CO2 or inc BiCarb
What happens to PO2 when PCO2 rises?
Blood pH dec
PCO2 dec
blood pH rises (basic)
O2 saturation can be used to calculate what parts of the acid-base balance?
Base excess/deficit
Sum of metabolic anions: Hgb, protein, PO4 and BiCarb
Typical cause and compensation mechanism for metabolic acidosis?
DKA, Lactic acidosis
Hyperventilate
Typical cause and compensation mechanism for metabolic alkalosis?
Vomiting
Hypoventilate
Typical cause and compensation mechanism for respiratory acidosis?
COPD; respiratory paralysis
Inc H secretion, BiCarb retention
Typical cause and compensation mechanism for respiratory alkalosis?
Anxiety; pain
Dec H Secretion, excretion of BiCarb
Causes of Metabolic Acidosis
DKA Lactic acidosis Meth/Ethyl glycol poison RF Diarrhea
Causes of Metabolic Alkalosis
Vomit
Diuretic therapy
Hyperadrenocortical Dz
Exogenous base excess
Causes of Respiratory Acidosis?
Emphysema
Pneumonia
Pulmonary Fibrosis
COPD
Causes of Respiratory Alkalosis
Hysteria
Fever
Salicylate poisoning
Asthma
What is the primary role of the carbonic acid-bicarbonate buffer system?
Prevent pH change from organic/fixed acids in ECF
How do the kidneys respond to respiratory acidoses when pulmonary response is ineffective?
Inc rate of H secretion into filtrate
Done with
Lect 1-3 for this Card Deck