chemistry and UA pre final

Bilirubin

• Conjugated bilirubin is the only form excreted by the kidneys and found in urine

• Uncontested bilirubin cannot be excreted by the renal system

Unpreserved urine

• will show increase in bacteria

• Cellular components will degrade or lyse

• Red and white blood cells will be decreased and bacteria will be increased

Urinary casts

• As urine flow decreases, filtrate is becomes concentrated and proteins builds up in the tubules

• Urinary casts are formed in the nephrons due to urine stasis and protein accumulationUA Protein Dipstick = ++

• Rbc casts will show blood on dipstick

• WBC casts will show leukocyte esterase on dipstick.

Waxy casts

• brittle consistency

• Visible cracks and jagged edges

• UA Correlation

  • Protein +

  • RBCs

  • WBCs

  • Cellular casts

• Granular casts

• Can indicate chronic renal failure

Broad casts

• Renal Failure Casts

  • Indicate destruction and widening of the tubular walls

  • Extreme urine stasis

  • UA Correlation

    • Protein +

    • RBCs

    • WBCs

    • Cellular casts

    • Granular casts

    • Waxy casts

  • Pathological

    • Extreme urine stasis

    • Chronic Renal Failure

Triple phosphate found in alkaline urine

Uric acid, found in acidic-neutral urine

Calcium oxalate found in acidic-neutral urine

Calcium carbonate found in alkaline urine

1L is how many mL

1000

0.001L is how many mL

1mL

1mL is how many uL

1000uL

0.001mL is how many uL?

1uL

How many microliters are contained in 2mL?

2000uL

A 1 to 6 dilution must be prepared to make a total volume of 800uL. How much patient sample is used?

1/6 × 800uL=133uL

Reference interval

The interval of values that includes 95% of reference sample results

Normal Range

Represents expected values for healthy individuals

Based on the patient population served by the laboratory

When do we reject a QC result?

• Any result > 3SD from mean

• 2 results > 2SD from mean

Potentiometry

• Uses ion selective electrodes

• Used for electrolytes (potassium, chloride)

22S

• QC failure must be resolved prior to patient testing

• May indicate systemic error

Systemic error

• Check reagent levels, expiration dates

  • As reagents deteriorate, QC may fail

• Ensure no analyzer alarms are present

Immunoassay

Binding of an antibody (Ab) to antigen (Ag) for the specific and sensitive detection of an analyte

Epitope

Site on the antigen (Ag) that binds to the antibody (Ab)

Immune complex

Antigen (Ag) bound to the antibody (Ab)

Insulin

• Synthesized by beta cells of islets of Langerhans in pancreas

• Only hypoglycemic agents (works to lower blood sugar)

Glucagon

• synthesized by alpha cells of islets of Langerhans in pancreas

• Hyperglycemic agent (increases blood sugar)

Glucogenesis

• Energy later today

Glycogen

Stored in the liver

Type 1 diabetes mellitus complications

• prone to diabetic ketoacidosis (DKA)

Type 2 diabetes mellitus complications

Generally no ketones present

Type 2 diabetes

• obesity

• Usually in adults

Type 1 diabetes

• in children < 20 yrs old

• Insulin deficiency

• Autoimmune disorder (beta cells in the pancreas are destroyed)

Ketones

• produced by the liver during gltyconegenesis

• Metabolism of fat for energy

Cholesterol

Found in virtually all cells of the body

Structural component of cell membranes
Precursor for many hormones

LDL

Carries the majority of cholesterol

Transports cholesterol from liver to tissues that need it
"Bad Cholesterol" - Deposits cholesterol in arteries

HDL

Removes excess cholesterol from cells and transports it for excretion

"Good Cholesterol

Triglycerides

Energy storage - 95% of fat is stored as triglycerides

Endogenous and Exogenous lipids

What is tested for on a lipid panel?

Cholesterol, LDL, HDL, triglycerides

VLDL-very low density lipoproteins

Transports endogenous triglycerides from liver to tissues

Direct bilirubin (total bilirubin)

• Conjugated (direct) bilirubin is water soluble

• Found in plasma in a free state

Indirect bilirubin

• Unconjugated (indirect) bilirubin is water insoluble

• Bound to albumin in circulation

If the total measured bilirubin is 5.0 mg/dL, and the direct (conjugated) bilirubin is 1.5 mg/dL, what is the concentration of indirect (unconjugated) bilirubin?

• Total Bilirubin = Direct (Conjugated) Bilirubin + Indirect (Unconjugated) Bilirubin

• 5.0=1.5+x

• 3.5= unconjugated bilirubin value

Urea/BUN

• Primary metabolite of protein breakdown

• Excreted through kidneys

• Urea/BUN make up 50% of NPNs

Creatine

• Waste product from creatine and creatine phosphate

• Proportional to muscle mass

• Filtered by glomeruli

eGFR

• Calculated result

• Based on serum creatinine, age, gender, body size and race

Ammonia

• Precursor to urea

• Produced in renal tubular epithelial cells

• Elevated in renal failure

What is used to evaluate renal function?

Urea/BUN, creatinine, eGFR, ammonia

Creatinine clearance range

• Males

  • 97 - 137 mL/min

• Females

  • 88 - 128 mL/min

Decreased creatinine clearance indicates

• Decreased glomerular filtration rate (GFR)

• Due to acute or chronic damage to glomeruli

Post renal azotemia

• Increase BUN due to something after the kidneys

  • Obstruction prevents urinary excretion

  • Kidney Stones

  • UTIs

  • Tumors of bladder or prostate

    congestive heart failure

Renal azotemia

Issue in kidney itself

• BOTH BUN and Creatinine are accumulating due to renal damage

• Proportional increase in BOTH BUN & Creatinine = Normal Ratio

• Renal disease

Post renal azotemia

Kidney stones

Urine Osmolality

High Urine Osmolality = High Amount of solute

Both SG and Osmolality measure concentration of urine

Complementary analytes that indicate how well kidneys are responding to maintain fluid balance

High Osmolality

• dehydration

• Glucosuria, diabetes mellitus

• Hypernatremia, increased sodium

Acute phase reactants

• globulins may function as them

• Increase in acute and sometimes chronic reactions

  • inflammation

  • infection

Tertiary proteins structure

Determines chemical and physical properties of the protein.

Creatine kinase (CK)

• CK-MM skeletal and cardiac

• CK-BB brain and CNS

• CK-MB cardiac muscle

ALT

• Liver

• Acute Viral Hepatitis
  Fatty Liver Disease
  Toxin/Drug Induced Liver Injury

• MOST SPECIFIC indicator of liver disease
  Most elevated in acute hepatitis

AST

• Liver, Heart, Skeletal Muscle

• Alcoholic Hepatitis
  Myocardial Infarction
  Severe Muscle Trauma

• Found in many tissues, less specific for liver disease
  AST can be > 2x ALT in alcoholism

ALP

• Liver, Bone

• Liver Disease
  Bone Disease
  Pregnancy

• Found in many tissues, dependent on age and patient sex

Pancreas has endocrine and exocrine functions:

Endocrine = Hormonal

• Pancreatic Hormones from Islets of Langerhans

• Alpha Cells = GLUCAGON

• Beta Cells = INSULIN

• Exocrine= enzymatic /digestive

Cushings disease

Dexamethasone suppression test

• Dexamethasone is a potent synthetic hormone that suppresses cortisol production

• Administer dexamethasone and monitor cortisol levels

• Anterior pituitary tumor

• Increased cortisol level

Parathyroid hormone

Maintains ionized calcium levels

• Increases bone resorption

• Reduces renal excretion

• Increases intestinal absorption

Increased parathyroid hormone

• Increased Calcium resorption in bones

• Decreased Calcium excretion in kidneys

• Increased Calcium absorption in intestines

Chloride sweat test

Pilocarpine stimulates sweating

Increased sweat chloride in Cystic Fibrosis

Calcium metabolism 3 Maine hormones

• Parathyroid hormone (PTH)

• Vitamin D

• Calcitonin

Calcium homeostasis

• Parathyroid hormone increased calcium levels

• Calcitonin has decreased calcium levels

Serum iron

Iron in circulation, bound to transferrin

TIBC

Reflects amount of transferrin available to bind iron

Saturation

Reflects amount of iron present in relation to the amount of transferrin available

Ferritin

Reflection of stored iron

Anion gap

Na+ - (CI + HCO3)

Measured cations

Na+ and K+ ( sodium is main one)

Measured anions

CI- and HCO3 (chloride is Main one)

Blood gas analysis

• Tubes left standing at room temperature will show changes in blood gases due to respiration by the RBCs

• Low P02

• High PCO2

• Low pH