chemistry and UA final review

White blood cell cast

Granular cast

Cholesterol casts

Hematuria

Presence of RBCs in urine

• Damage to kidney or genitourinary tract

  • Renal calculi (kidney stones)

  • Glomerular disease

  • Pyelonephritis

• Strenuous exercise

• Microscopic will see intact RBC

Hemoglobinuria

Presence of free hemoglobin in urine

• RBC lysis in dilute urine

• Intravascular hemolysis

  • Hemolytic anemia

  • Transfusion Reactions

  • Severe burns

  • Infections

  • Brown recluse spider bite

• Strenuous exercise

• Microscopic will see no RBCs or cremated RBCs

Myoglobinuria

Myoglobin is a heme-containing protein found in muscles

• Rhabdomyolysis

  • Trauma

  • Crush Injuries

  • Convulsions

• Extreme physical exertion

• Microscopic will see no RBCs

Dilutions

Dilution: Represents the part(s) of a concentrated material to the total final volume of a solution

• Parts of substance being diluted in the total number of parts of the solution

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

133uL of patient sample

Percent solutions

percent solutions implies parts per 100 which is independent of the molecular weight.

Example of percent solutions: How many grams of NaOH are present in a 10% w/w solution?

10g NaOH

Molar solutions

g= (gmw) (M) (v)

Molar solution example: A solution contains 300g of NaOH per liter. What is the molar concentration? Na= 23, O= 16, H=1

• 23+16+1=40g/mol

• 300g=(40g/mol) (x) (1L)

• 300=40x

• 7.5M solution

Making a new solution from existing: How many mL of a 5M solution of NaOH are needed to make 100 mL of a 2M NaOH?

• C1= 5M, V1= xmL, C2=2M, V2= 100mL

• (5)(xmL)= (2M)(100mL)

• 40mL stock solution

When do we reject QC result?

• Any result > 3SD from mean

• 2 results > 2SD from mean

When do we accept QC result?

• any single result within + or - SD of the mean

Trichomonas

• undulating membrane

• Jerking motility

• 4 flagella

normal CSF glucose

• 60-80% plasma glucose level

• Should be compared to blood glucose

Low CSF glucose

• can indicate bacterial meningitis

Peritoneal fluid

• aka ascites

Quality control materials

• QC Materials have little variation between vials of the same lot number

• QC Materials span normal and abnormal ranges

  • Two levels of QC is the minimum

analytical measurement range (AMR) vs. clinical reportable range

• AMR (aka Linear Range): Determined by calibration of an assay

• Clinical Reportable Range: Extended reportable range to include values obtained by dilution

Beers law spectroscopy

• Concentration of a substance is directly proportional to the amount of light absorbed

Potentiometry

• ion selective electrodes

• For electrolyte measurement

• Changes depending on number of electrolytes in patient sample

Immunoassay

• hormone testing

Insulin

• Synthesized by beta cells of islets of Langerhans in pancreas

• Primary hormone responsible for glucose entry into the cell

• ONLY hypoglycemic agent

Glucagon

• Synthesized by alpha cells of islets of Langerhans in pancreas

• Primary hormone responsible for increasing serum glucose

• Hyperglycemic agent

Hemoglobin A1C

• represents average blood glucose levels over 2-3 months

• RBC life span is 120 days

Which pancreatic hormone causes a DECREASE in blood glucose / glucose in circulation?

Insulin

Which pancreatic hormone causes an INCREASE in blood glucose / glucose in circulation?

Glucagon

Which pancreatic hormone is produced in the beta cells of the islets of langerhans?

Insulin

Which pancreatic hormone is produced in the alpha cells of the islets of langerhans?

Glucagon

Glycolysis

Metabolism of glucose for energy NOW

Glycogenolysis

Metabolism of glycogen to glucose

Glycogenesis

Conversion of glucose to glycogen, regulates blood sugar through the day

Gluconeogenesis:

• Formation of glucose from non-carbohydrate sources, "building supplies" for energy

Type 1 diabetes mellitus

• Usually under 20 years old

• Prone to diabetic ketoacidosis

• Autoimmune disorder

• Beta cells in pancreas are destroyed

• Lacks insulin

Risk factors for coronary artery disease

• high blood pressure

• Diabetes mellitus

• Obesity

• Other atherosclerotic diseases

• Low HDL (good cholesterol)

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

Phospholipids

• Important component of the outer shell of lipoproteins

• Amphipathic

  • Hydrophilic and hydrophobic components

  • Function as biological stabilizers and surfactants

    • Reduces surface tensions in the body

    • Pulmonary surfactant for gas exchange

Phospholipids are found in:

• Fetal lung maturity

• Lecithin/sphingomyelin ratio (L/S ratio)

Lipids

• Nearly insoluble in water

• Soluble in organic solvents

Ketones

• production in type 1 diabetes mellitus

• Produced by the liver during glyconeogenesis

  • Metabolism of fat for energy

Protein synthesized in:

Liver

Creatinine

• Waste product from creatine and creatinine phosphate

• Synthesized in the liver

• Good indicator of Renal Function because:

  • Freely filtered by the glomeruli

  • Not reabsorbed

  • Excreted at a relatively predictable rate

Creatinine clearance

CrCI= (urine creatinine (mg/dL)/serum creatinine) X total urine volume/ period X 1.73/BSA

Given the following information, calculate the creatinine clearance for an average adult-sized [\(1.73\text{ m}^2\)] patient:

• Urine Creatinine = 165

• Plasma Creatinine = 1.8

• 24 hr Urine Volume = 950

• 165/1.8 X 950/1440 X 1.73/1.73 =60.475

• This is a low result

Low creatinine clearance indicates

• low GFR and can mean acute or chronic renal damage

Renal azotemia

• high BUN

• high creatinine

• Leads to normal BUN: creatinine ratio

• Nephrotic syndrome

Nephrotic syndrome

• Damaged glomeruli become permeable to large molecules that are normally reabsorbed in healthy glomeruli

• Massive Proteinuria

• Renal azotemia

Hyperiricemia can result in:

Gout

• Due to chronic hyperuricemia

  Inflammatory arthritis due to the accumulation of crystals in joints and surrounding tissues

Non protein nitrogen’s (NPNs)

• urea

• Uric acid

• Creatinine

• Ammonia

Microalbumin

• first indicator of renal disease

• Predictor of diabetic nephropathy in diabetes mellitus

Osmolal gap

• Difference between measured osmolality and calculated osmolality

• Measured Osmolality:

  • Freezing point depression

Direct bilirubin (conjugated)

• Conjugated (direct) bilirubin is water soluble

• Found in plasma in a free state

Indirect bilirubin (unconjugated)

• Unconjugated (indirect) bilirubin is water insoluble

• Bound to albumin in circulation

Bilirubin cycle

• Bilirubin is a product of hemoglobin breakdown

• Bilirubin binds to albumin in circulation - unconjugated [indirect] bilirubin

• Bilirubin is transported to the liver for conjugation/excretion

Zero order kinetics

• Linear Phase

• Constant Rate

• All available enzyme (analyte) is reacting with substrate

• We are using this phase of constant reaction to measure the enzyme/analyte

Inhibitors

• enzyme is test analysts acts on substrate reagent

• Bind to components of a reaction to slow down or stop the enzyme ability to catalyze a reaction

Competitive

• physically similar to substrate (reagent) binds to active site on enzyme (analyte)

Non-competitive

Binds on allosteric site of enzyme [analyte], changing enzyme structure so substrate [reagent] cannot bind

Uncompetitive

• Helpful" Inhibitor

• Binds to the enzyme (analyte) - substrate (reagent complex)

• Prevents release of product (no re-using the enzyme!)

BNP (AKA NT-proBNP

• response to stretch from fluid overload

• Brain natriuretic peptide

• BNP and NT-proBNP used to confirm diagnosis of congestive heart failure (CHF)

Cardiac markers after AMI

• first is Myoglobin

• CK-MB is second (peaks at 18 hours)

• Troponin (peaks at 10-24 hours)

CK-MB

Peaks at 18 hours, normalizes in 2 days

Troponin

Peaks at 10-24 hours, normalizes in 4 days

ALT

• most specific for liver disease

Growth hormone abnormality

• Pituitary Gigantism

  • Rapid, abnormal height and growth well above peers

  • Large hands and feet, prominent forehead and coarse facial features

  • Vision problems, frequent headaches due to pituitary tumor

  • Overproduction of Growth Hormone by posterior pituitary gland

Free Thyroxine (T4)

• Unbound T4= physiologically active

Thyroid hormones

Most travel bound to carrier proteins

• Thyroxine-binding globulin (TBG)

• Albumin

• Thyroxine-binding pre-albumin (TBPA)

Hypothyroidism

• high TSH and low T4 and T3

Hyperthyroidism

Low TSH, high T3 and T4

Primary hyperthyroidism (Graves’ disease)

• thyroid over produces biologically active T3 and T4

• Up T4 and T3

• Decreased TSH

Catecholamines

• secreted by adrenal macula

• Epinephrine

• Norepinephrine

• Dopamine

Addison disease

• adrenal glands don’t produce cortisol

Cushing’s syndrome

Adrenal gland overproduces cortisol

Prostate specific antigen (PSA)

• prostate cancer screening

Alpha-fetoprotein (AFP)

Hepatocellular cancer (liver)

CEA

• cororectal, GI, pancreatic, breast cancers

CA 19-9

• GI, breast cancer

Potassium test interferences

• Critically high potassium is > 6

• Hemolysis falsely increases potassium

• CHECK FOR HEMOLYSIS

Chloride sweat test

• pilocarpine stimulates sweating

• Increased In cystic fibrosis

Ion selective electrodes

• measures electrolytes (sodium, chloride)

Major cation is?

Sodium (Na+)

Major anion is

Chloride (CI-)

Calcium and phosphorus

• Are inversely related

• High calcium would have low phosphorus

Ionized calcium

• physiologically active form of calcium

Calcium hormones

• Parathyroid hormone (PTH)

• Vitamin D

• Calcitonin

TIBC

Reflects amount of transferrin available to bind iron

Ferritin

• iron stored

Normal pH

7.35-7.45

HCO3 normal range

22-26

Alkalosis

• high pH

Respiratory

Opposite reactions

Metabolic

Same reaction

Acidosis

Low pH

Anion gap

• Na+ - (CI- + HCO3-)

• Consist of sodium, chloride, potassium, bicarbonate