Clinical Chemistry Final

What one item must be remembered when handling a tube of blood?

gloves & lab coat

The major causes of decreased plasma urea concentration include:

low protein intake & severe liver disease

A patient sample for uric acid gave an absorbance reading of 0.4; the 50 mg/dL standard used in the test gave an absorbance reading of 0.1. What is the concentration of uric acid in the patient's sample in grams per deciliter?

0.2

An electrolyte panel was performed on a patient in the ER. The following values were reported: Sodium: 150 mEq/L Chloride: 110 mEq/L Potassium: 5 mEq/L Bicarbonate: 30 mEq/L The anion gap (without using K) for this patient is:

10 mEq/L

A patient brought to the emergency room has the following lab results: Sodium: 140 mmol/L BUN: 6.0 mg/dL Glucose: 80 mg/dL Osmolality: 316 mOsm/Kg H20 The calculated osmolality on this patient using the Weisberg formula is:

286

The coefficient of variation for the above statistics is:

4%

Serum glucose determinations are done on samples from a control pool each day for 30 days. Quality control statistics are then calculated. The mean is 10 mg/dL and the standard deviation is 4 mg/dL. These statistics are used to label a quality control chart for the mean and a +2 SD. Samples from the same control pool are then assayed each day alone with patient samples, and control results are plotted on the chart. Results for the first 10 days are as follows: Day 1 - 96 Day 2 - 97 Day 3 - 95 Day 4 - 107 Day 5 - 106 Day 6 - 107 Day 7 - 89 Day 8 - 103 Day 9 - 106 Day 10 - 105 Using 95% confidence limits means that 95% of the control values would fall between:

92 - 108

Protein hormones exhibit all of the following characteristics EXCEPT?

A long halflife

On day 4 above, the light source was changed in the spectrophotometer used for this procedure. The results seen in the quality control after that day are called:

A shift

Which of the following hormones is secreted by the posterior pituitary gland?

ADH

Elevations in which of the following are MOST likely to indicate liver disease?

AST, ALT & ALK phosphatase

Which of the following compounds is (are) not considered protein hormones?

Aldosterone only

Universal precautions should be observed when working with:

All patients

The acute phase reactant protein that also inhibits proteolysis and has the highest concentration within its globulin fraction is:

Alpha-antitrypsin

In a spectrophotometric determination, which one of the following is the formula for calculating the absorbance of a solution?

Beer formula

Common clinical lab methods for the measurement of serum albumin are based on the properties of albumin as a/an:

Binding protein

The old T3 resin uptake test has been replaced by a direct assay for:

Bound T3

Given the following lab results, what is the most likely cause of this patient's BUN? BUN 45 mg/dL Creatinine 1.8 mg/dL Uric acid 7 mg/dL pH 7.22 pCO2 74.4 mm Hg pO2 32.8 mm Hg O2 sat 51.3%

CHF

You just received a blood specimen from the ER. According to the requisition, the patient had overdosed on an antacid medication containing bromide salts. You have been asked to run a STAT set of electrolytes on the serum. Which electrolyte would most likely be falsely elevated?

Chloride

The parent substance of all steroid hormones is:

Cholesterol

A laboratory fire ignited by faulty wiring in a chemistry analyzer and partially fueled by surrounding paper products is classified as:

Class A & C

A genetic disorder causing a deficiency of certain enzymes in the synthetic pathways leading to cortisol and aldosterone production is referred to as:

Congenital Adrenal Hyperplasia

Hyponatremia (low serum sodium level) may be found in all of the following conditions EXCEPT:

Conn's Syndrome

Pituitary secretion of adrenocorticotropic hormone (ACTH) is inhibited by elevated levels of:

Cortisol

A hemolyzed specimen is received in the laboratory for enzyme analysis. The assay for which of the following enzyme values would be affected by hemolysis?

Creatinine kinase

One cause for a DECREASED "anion gap" is:

Decrease in albumin

A plasma specimen from a hospital patient is analyzed on an osmometer and reported as 400 mOsm/Kg. What is the most likely effect on this patients water distribution in the tissues

Dehydration

When finished with lab exercises for the day, which order of events should be followed?

Disinfect area, remove gloves, remove lab coat, and wash hands

Which of the following best describes the correct collection and handling conditions for a blood ammonia measurement?

Draw Heparin tube, keep on ice, test immediately

True or False? A patient's blood urea nitrogen (BUN) was 50 mg/dL on Day 1, and the control serum for BUN was within 2 SD of the mean on that day. On Day 2, the same patient's BUN was 70 mg/dL; again, the control value was acceptable. Should the physician interpret this increase in the BUN as a real pathologic change in the patient? (The only control level available for this test has a mean value of 20 mg/dL and a SD of 2 mg/dL).

False

True or False? Individuals taking recurring regimens of androgens or anabolic steroid drugs may exhibit increased TBG levels.

False

Of the following protein fractions, the one that is NOT produced in he liver is:

Gamma globulin

Which of the following is a tropic (stimulating) hormone?

Growth hormone

An example of ectopic hormone production would be:

Growth hormone production by lung tumors

Which of the following has the highest incidence of infectious risk in the clinical lab?

Hepatitis B

Which of the following methods for glucose is the most common:

Hexokinase

The secretion of hormones from the anterior pituitary is largely controlled by circulating levels hormones from the target gland and hormones secreted by the:

Hypothalamus

In a patient suspected of having primary hyperthyroid myxedema, one would expect the following serum results: T4 ___________, TSH _________.

Increased; decreased

In a patient with suspected primary hyperthyroidism associated with Graves' disease, one would expect the following lab serum results: T4 ___________, TSH __________.

Increased; decreased

The method of choice for measurement of serum ionized calcium is

Ion selective electrode

Which of the following enzymes has multiple molecular forms (isoenzymes) whose clinical significance is used in diagnosis?

LD, CK, Alkaline Phosphatase

An LD flip, in assessing a possible myocardial infarction, refers to:

LD1 > LD2

Which of the following statements regarding the clinical use of CK-MB (CK-2) is true?

Mass unit assays are more sensitive than electrophoretic methods

The chemical reaction phase does not include:

Measurement

The Component used to isolate a wavelength in a spectrophotometer is called a:

Monochromator

Face masks and protective eyewear are designed to offer protection from:

Mucus membrane contact

Which one of the following statements about T3 is FALSE?

Not bound to serum proteins

Calcium concentration in the serum is regulated endogenously by:

Parathyroid hormone

The TRH (thyrotropin releasing hormone) stimulation test is useful in differentiating hypothalamic hypothyroidism from:

Pituitary hypothyroidism

In the automated chemistry analyzer, data management is a function of:

Post-analytical phase

Which of the following electrolytes would be increased in the serum if the blood specimen was hemolyzed?

Potassium & phosphate

Pituitary adenomas that secrete ______________ are by far the most common form of hyperpituitarism.

Prolactin

What is the first feature of nephrotic syndrome that results in manifestation of the other four classic signs?

Proteinuria

On day 7, the control results are more than 2 SD from the mean. The first thing you would do is:

Rerun the control with the same reagent

The coefficient of variation (CV) is:

SD expressed as a % of the average of values used to calculate SD

A physician calls the lab and asks what tests should be requested to assess the acid-base balance function of a patient's renal system. You reply:

Serum bicarbonate & blood pH

Which activity can spread HIV or HBV from one person to another outside of the lab?

Sexual contact

What hormone inhibits TRH in the presence of increased levels of T3 and T4?

Somatostatin

Which of the following statements describes optimal conditions for transport, handling and storage of blood specimens for clinical chemistry testing?

Specimen brought to the lab immediately, permitted to clot, serum separated and tested ASAP

The most common non-reducing sugar is:

Sucrose

A two-year-old with a decreased serum T4 is described as being somewhat dwarfed, stocky, and overweight and having coarse features. Of the following, the most informative additional lab test would be serum:

TSH

The three levels of dysfunction that may be evaluated in a patient with an endocrine problem are primary, secondary, and tertiary. The possible defective sites that correspond to these primary, secondary, and tertiary levels of dysfunction are, respectively:

Target gland, pituitary, hypothalamus

The major fraction of organic iodine circulating in the blood is:

Tetraiodothyronine = T4

Diurnal variation is a term that refers to:

Time of day of specimen collection

Which MI marker is the most specific and sensitive and remains elevated for 14 days or more?

Troponin T

True or False? Serum uric acid levels may be elevated in patients undergoing cancer chemotherapy.

True

True or False? When taken by a euthyroid individual, oral contraceptives will have an increasing effect on thyroxine binding globunlin.

True

Each of the following factors influences the serum calcium concentration EXCEPT:

Tyrosine

A toxic condition involving a very high serum level of urea and accompanied by failure of the three main functions of the renal system is referred to as:

Uremia

The test for adrenal cortical hyperfunction that has the greatest diagnostic sensitivity is measurement of:

Urinary free cortisol

Bilirubin is reduced to __________ in the small intestine.

Urobilinogen

Which of the following does the most to minimize aerosol production during centrifugation?

Use stoppered centrifuge tubes or a cover over the rotor

The membrane substance used in the potassium ion-selective electrode is

Valinomycin

The FINAL metabolite of epinephrine that is measured in urine is:

Vanillylmandelic acid

Which of the following procedures is most basic and effective in preventing the spread of infectious diseases in the hospital environment?

Washing hands between patients

Ideally, the best type of centrifuge that separates blood cells and plasma for analysis in the clinical laboratory is:

a temperature-controlled centrifuge with spinning buckets that holds 5-10 ml blood tubes