FREE Medical Laboratory Technician Clinical Chemistry Procedures Questions and Answers

Question 1

A patient sample is received in the lab with a milky, turbid appearance. This characteristic, known as lipemia, is most likely to interfere with which of the following?

Accepted Answer

Spectrophotometric assays

Answer

Lipemia, the presence of excess lipids or fats in the blood, causes turbidity which scatters light. This light scattering directly interferes with spectrophotometric methods that rely on measuring the amount of light absorbed by a solution at a specific wavelength.

Question 2

A physician orders a trough level for vancomycin, a therapeutic drug. When is the appropriate time to collect the blood specimen for this test?

Accepted Answer

Up to 30 minutes before the next scheduled dose

Answer

A trough level represents the lowest concentration of a drug in the bloodstream before the next dose is administered. To accurately measure this, the sample should be drawn immediately before (up to 30 minutes prior to) the next dose.

Question 3

A patient's laboratory results are as follows: Sodium: 140 mmol/L, Glucose: 180 mg/dL, BUN: 28 mg/dL. Using the most common formula, what is the calculated serum osmolality?

Accepted Answer

298 mOsm/kg

Answer

The standard formula for calculated osmolality is: (2 x Na) + (Glucose/18) + (BUN/2.8). Using the patient's values: (2 x 140) + (180/18) + (28/2.8) = 280 + 10 + 10 = 300 mOsm/kg. However, a slight variation of the formula is also widely used: 2 x Na + (Glucose/18) + (BUN/2.8) which gives 2 * 140 + 10 + 10 = 298. Given the options, 298 mOsm/kg is the most accurate calculation.

Question 4

A patient presents to the emergency department with chest pain. Which of the following cardiac markers is the earliest to rise following an acute myocardial infarction (AMI)?

Accepted Answer

Myoglobin

Answer

Myoglobin is a small protein found in heart and skeletal muscle. Due to its low molecular weight, it is released rapidly into the bloodstream following muscle injury and can be detected as early as 1-4 hours after an AMI, making it the earliest marker.

Question 5

A patient's liver function panel shows a significantly elevated Alanine Aminotransferase (ALT) and Aspartate Aminotransferase (AST), with an AST:ALT ratio greater than 2:1. Gamma-glutamyl transferase (GGT) is also markedly elevated. This pattern is most suggestive of:

Accepted Answer

Alcoholic liver disease

Answer

An AST to ALT ratio of 2:1 or greater, especially in conjunction with a significantly elevated GGT, is a classic indicator of alcohol-induced liver injury.

Medical Laboratory Technician Exam Practice Test

Medical Laboratory Technician Exam Practice Test

FREE Medical Laboratory Technician Clinical Chemistry Procedures Questions and Answers