Clinical Chemistry

What is the metric conversion acronym and their values?

Don’t: Deci, -1

Catch: Centi, -2

Me: Milli, -3

Missing: Micro, -6

No: Nano, -9

Pants: Pico, -12

What is the metric conversion equation?

existing - desired = conversion factor

A negative conversion factor means you move the decimal to the ______ and a positive conversion factor means you move the decimal to the ______.

left

right

Convert 1 dL to microliters.

(-1) - (-6) = 5 (to the right)

1 dL = 100000 uL

Convert 1 uL to centiliters.

(-6) - (-2) = -4 (to the left)

1 uL = 0.0001 cL

How do you convert Fahrenheit into Celsius?

C = (F - 32) x (5/9)

Convert 54F to Celsius.

C = (54 - 32) x (5/9) = 40C

How do you convert Celsius into Fahrenheit?

F = (C x 9/5) + 32

Convert 28C int Fahrenheit.

F = (28 x 9/5) + 32 = 82F

How do you convert mg/dL into mEg/L?

mEg/L = mg/dL x 10 / equivalent weight

How do you calculate the equivalent weight?

equivalent wight = atomic weight / valence charge

How do you convert mg/dL into mmol/L?

mmol/L = mg/dL x 10 / molecular weight

A substance with an assigned value used to calibrate a machine is a:

standard (calibrator)

A sample whose composition is similar to a patient sample is a:

control

____________ is the reproducibility or repeatability of results.

Precision

_________ is how close a result is to the true value.

Accuracy

How do you calculate SD?

What percent of data points will fall within 1, 2, and 3 SD from the mean?

1 SD: 68%

2 SD: 95%

3 SD: 99%

What is the acceptable range or confidante limit for controls?

2 SD or 95% confidence limit

A ______ is when consecutive points start to increase/decrease at a constant rate on an L-J chart.

trend

A ______ is when consecutive points are consistently on one side of the mean.

shift

What Westgard rule is being broken?

1_2S - just a warning

What Westgard rule is being broken?

1_3S

What Westgard rule is being broken?

2_2S

What Westgard rule is being broken?

R_4S

What Westgard rule is being broken?

4_1S

What Westgard rule is being broken?

10_X

What is used to compare method for precision?

coefficient of variation (CV)

What is the acceptable range for CV?

0-5%

How do you calculate CV?

CV = 1 SD / mean x 100

The probability that a test result will be positive when disease the test is detecting is present is:

diagnostic sensitivity

How do you calculate diagnostic sensitivity?

sens% = [TP / (TP + FN)] x 100

The probability that a test result will be negative when the disease that the test is detecting is not present is:

diagnostic specificity

How do you calculate diagnostic specificity?

spec% = [TP / (TN + FP)] x 100

The ability of the test system to detect low concentrations of the analyte is:

analytical sensitivity

The ability of the test system to measure only the substance without false positives is:

analytic specificity

The chance of an individual having a disease or condition if the test is abnormal is:

positive predictive value

How do you calculate the positive predictive value?

PPV = [TP / (TP + FP)] x 100

The chance an individual does not have a disease or condition if the test is within the reference interval is:

negative predictive value

How do you calculate the negative predictive value?

[TN / (TN + FN)] x 100

What does the spectrophotometer measure?

measures transmittance of light and converts to absorbance

In the spectrophotometer, the light must first pass through the ____________, a device that selects a certain wavelength of light, before passing through the sample.

monochromator

The ____________ in the spectrophotometer reads the amount of light transmitted and converts light energy into an electrical signal.

photodetector

The ____________ in the spectrophotometer is the readout device that take the electrical signal from the photodetector and converts it into a measurable number.

galvanometer

What are the 2 principles of Beer’s Law?

1. concentration is directly proportional to absorbance

2. concentration is inversely proportional to transmitted light

What is the Beer’s Law equation?

Cu = (Au / As) x Cs

Cu = concentration unknown

Au = absorbance unknown

As = absorbance standard

Cs = concentration standard

How do you convert % transmittance into absorbance?

A = 2 - log %T

On a Beer’s Law standard curve, absorbance is on the __ axis and concentration is one the __ axis.

y

x

What should you do if a patient sample is outside the linearity for the spectrophotometer?

1. dilute specimen and rerun

2. final concentration = new concentration x DF

What method is used to measure light absorbed by ground state atoms?

atomic absorption spectrophotometry

What method measures the light emitted from compounds that absorb electromagnetic radiation, become excited, and then return to energy state lower than their original energy state?

fluorometry

In fluorometry, the wavelength of emitted light is _______ than the wavelength of absorbed light.

longer

What method measures the blockage of light as particles pass through the cuvette in a spectrophotometer?

turbidimetry

In nephelometry, forward scatter measures cell ______.

size

In nephelometry, forward scatter measures cell ______.

complexity

What method measures total number of dissolved particles in a solution based on colligative properties like freezing point depression?

osmometry

In osmometry, higher concentrations correlate with _______ freezing points.

lower

What is the absorption of a drug to a solid medium and elution by a mobile, liquid phase?

chromatography

What method separates proteins based on ionic charge?

electrophoresis

When performing electrophoresis, proteins will have a __________ charge when in an alkaline environment, causing them to migrate towards the _______.

negative (anion)

anode

What method uses an ion selective electrode (ISE) to measure electrolytes. What membrane is selective for Na⁺? Which membrane is selective for K⁺?

potentiometry

Na⁺ - glass

K⁺ - valinomycin

What is the major source of energy for the body and brain?

glucose

What is the normal range for fasting blood glucose (FBS)? What value indicates diabetes mellitus?

70-110 mg/dL

≥ 126 mg/dL

What are the critical values for fasting blood glucose (FBS)?

< 50 mg/dL

> 500 mg/dL

What is the normal range for random/casual blood glucose? What value indicates diabetes mellitus?

70-130 mg/dL

≥ 200 mg/dL

What is the normal range for postprandial blood glucose (2 hours after eating)? What value indicates diabetes mellitus?

70-110 mg/dL

≥ 200 mg/dL

What is the normal range for HbA1c? What value indicates diabetes mellitus?

< 7.0%

> 12%

What enzyme breaks down carbohydrates into glucose and monosaccharides?

amylase

Glucose is stored in the liver as:

glycogen

When the storage capacity for glycogen has been reached, it is converted into fat and stored as ____________ in adipose tissue.

triglycerides

__________ is when glucose is metabolized into lactic and pyruvic acids.

• glycolysis

• glycogenesis

• glycogenolysis

• gluconeogenesis

Glycolysis

__________ is when glucose is converted into glycogen.

• glycolysis

• glycogenesis

• glycogenolysis

• gluconeogenesis

Glycogenesis

___________ is when glycogen is broken down into glucose.

• glycolysis

• glycogenesis

• glycogenolysis

• gluconeogenesis

Glycogenolysis

____________ is when fats and proteins (non-carbohydrates) are broken down into glucose.

• glycolysis

• glycogenesis

• glycogenolysis

• gluconeogenesis

Gluconeogenesis

What is the only hormone that decreases blood glucose?

insulin

What hormone is produced in alpha cells and increases blood glucose?

• glucagon

• cortisol

• epinephrine

• growth hormone

• thyroxine

glucagon

What hormone increases blood glucose by stimulating protein catabolism and gluconeogenesis?

• glucagon

• cortisol

• epinephrine

• growth hormone

• thyroxine

cortisol

What hormone increases plasma glucose by responding during increased stress?

• glucagon

• cortisol

• epinephrine

• growth hormone

• thyroxine

epinephrine

What hormone produced in the anterior pituitary increases glucose levels by acting as an antagonist to insulin?

• glucagon

• cortisol

• epinephrine

• growth hormone

• thyroxine

growth hormone

What hormone increases absorption from the GI tract and promotes glycogenolysis?

• glucagon

• cortisol

• epinephrine

• growth hormone

• thyroxine

thyroxine

What disease is caused by a deficiency in arginine vasopressin hormone (AVP)?

diabetes insipidus

What disease is caused by the absolute or relative deficiency of insulin that causes hyperglycemia?

diabetes mellitus

Type __ diabetes mellitus is caused by destruction of beta cells in the pancreas, causing absolute deficiency of insulin.

type 1

Type __ diabetes mellitus requires insulin treatments.

type 1

Type __ diabetes mellitus has juvenile onset.

type 1

Type __ diabetes mellitus is associated with a genetic predisposition.

type 1

Type __ diabetes mellitus has a greater tendency to produce ketones.

type 1

___________ occurs when the body excessively utilizes fats because it cannot utilize carbohydrates effectively for energy. This causes the body’s pH to decrease.

Ketoacidosis

How does ketoacidosis effect osmolality?

increases due to loss of water = increased concentration of particulate in blood

Ketoacidosis causes what 2 electrolyte imbalances?

1. hyponatremia (decreased plasma sodium)

2. hyperkalemia (increased plasma potassium)

Type __ diabetes mellitus is caused by an individual’s resistance to insulin, resulting in relative insulin deficiency.

type 2

Type __ diabetes mellitus is treated with weight reduction, diets, and oral medication.

type 2

Type __ diabetes mellitus is often associated with obesity.

type 2

Type __ diabetes mellitus has adult onset.

type 2

Majority of people with diabetes mellitus have type __.

type 2

____________ occurs when the blood glucose levels exceed the renal threshold, causing the proximal tubules to no longer be able to reabsorb the excess, causing glucose to be excreted in the urine.

Glycosuria

Glycosuria occurs when the glucose blood levels exceed the normal renal threshold of:

160-180 mg/dL

Plasma glucose levels of _________ indicate hypoglycemia.

< 50 mg/dL

What is the reference method for measuring glucose?

hexokinase method

In the hexokinase method, the reagent _______ is added to reduce NAD to NADH.

G-6-PD