MLT GlobeASCP exam preparation (USA · MLS / MLT) – page 14
1200 practice MCQs for the ASCP medical laboratory exam. Level: Advanced.
Apheresis is a collection method in which:
An apheresis machine draws blood, separates out the chosen component (such as platelets or plasma) and returns the rest to the donor.
Until all donor screening tests are completed and negative, collected units are kept:
Untested units are quarantined so they cannot be issued by mistake. They are released only after all mandatory tests are negative and labeling is complete.
Acute transfusion reactions are those that occur within:
Reactions within 24 hours are called acute. Those appearing later (such as delayed hemolysis or TA-GVHD) are called delayed.
After a suspected transfusion reaction, which items should be sent to the blood bank?
The bag and set allow rechecking and culture of the unit, and the post-transfusion sample is used for clerical checks, hemolysis check, DAT and repeat grouping.
Febrile non-hemolytic transfusion reactions are best reduced by using:
Most febrile reactions are caused by donor white cells or the cytokines they release during storage. Leukoreduction before storage greatly reduces them, while irradiation does not.
Which is an infectious complication of transfusion?
Hepatitis C is a transfusion-transmitted infection, which donor screening aims to prevent. The other options are non-infectious reactions.
The most frequent form of HDFN is:
ABO HDFN, mainly in group A or B babies of group O mothers, is the most common form but is usually mild.
Type 1 diabetes mellitus is mainly caused by:
Type 1 diabetes results from autoimmune destruction of insulin-producing beta cells, causing absolute insulin deficiency. Insulin resistance is the main feature of type 2 diabetes.
In diabetic ketoacidosis, which ketone body is present in the blood in the highest concentration?
Beta-hydroxybutyrate is the predominant ketone body in DKA. It is not detected by the nitroprusside reaction, which reacts mainly with acetoacetate. Lactate is not a ketone body.
Polyuria in uncontrolled diabetes mellitus is mainly due to:
When plasma glucose exceeds the renal threshold, filtered glucose stays in the tubule and draws water with it (osmotic diuresis), producing large urine volumes.
Which lipoprotein is often called 'bad cholesterol' because it carries cholesterol to peripheral tissues?
LDL is the main carrier of cholesterol to tissues, and high LDL promotes atherosclerosis. HDL removes cholesterol from tissues and is called 'good cholesterol'.
A triglyceride molecule is made of:
Triglycerides (triacylglycerols) are three fatty acids esterified to one glycerol backbone. Sphingosine is the backbone of sphingolipids.
In enzymatic triglyceride methods, triglycerides are first hydrolysed by which enzyme?
Lipase hydrolyses triglycerides to glycerol and free fatty acids; the glycerol is then measured through glycerol kinase and further coupled reactions.
Lipoprotein lipase on capillary walls hydrolyses the triglyceride carried in which lipoproteins?
Lipoprotein lipase, activated by apo C-II, removes triglyceride from the triglyceride-rich lipoproteins, chylomicrons and VLDL. LDL and HDL are cholesterol-rich.
Which is the most abundant protein in normal human plasma?
Albumin makes up roughly 55–60% of total plasma protein, more than any other single protein.
Which protein is present in plasma but absent from serum?
Fibrinogen is converted to fibrin and removed in the clot, so serum lacks it. The other proteins remain in serum.
Which creatine kinase isoenzyme is found mainly in the brain?
CK-BB is the main isoenzyme of brain and smooth muscle. CK-MM predominates in skeletal muscle, and CK-MB is found in highest proportion in heart muscle.
Serum gamma-glutamyltransferase (GGT) is mainly used as a marker of:
GGT is a sensitive marker of liver and biliary disease and is induced by alcohol. It is not raised in bone disease, which helps localise a raised ALP.
Which enzyme conjugates bilirubin with glucuronic acid in the liver?
UDP-glucuronyltransferase (UGT1A1) adds glucuronic acid to bilirubin in hepatocytes. Heme oxygenase and biliverdin reductase act earlier, in bilirubin formation.
The approximate upper reference limit for total serum bilirubin in adults is:
Adult total bilirubin is normally below about 1.0–1.2 mg/dL (17–21 µmol/L); exact limits vary slightly by method.