Mixed Deck — All MLPAO Topics Flashcards

Which liver enzyme is most specific for biliary obstruction?

Answer: 5'-Nucleotidase

5'-Nucleotidase is the most specific enzyme for biliary obstruction because it is primarily found in hepatobiliary tissue. While alkaline phosphatase and GGT are also elevated in cholestasis, they can be elevated in bone disease and other conditions respectively.

What is the clinical significance of a low glucose level in pleural or peritoneal fluid?

Answer: Fluid glucose <3.3 mmol/L or fluid/serum ratio <0.5 suggests bacterial infection, tuberculosis, rheumatoid pleurisy, or malignancy

Low glucose in body fluids indicates consumption by bacteria (empyema, SBP), high metabolic activity of inflammatory cells (rheumatoid pleurisy, TB), or utilization by malignant cells. In pleural fluid, glucose <3.3 mmol/L is associated with complicated parapneumonic effusion requiring drainage. In ascitic fluid, low glucose suggests secondary bacterial peritonitis.

An antibody screen is positive at the antiglobulin (AHG) phase. The antibody identification panel shows reactivity with all Jk(a)-positive cells and no reactivity with Jk(a)-negative cells. What is the antibody?

Answer: Anti-Jk(a)

The reactivity pattern — positive with all Jk(a)-positive cells and negative with all Jk(a)-negative cells — identifies anti-Jk(a). Kidd antibodies are clinically significant, cause complement-mediated hemolysis, and are notorious for evanescence (dropping to undetectable levels). Jk(a)-negative, crossmatch-compatible units must be provided.

A specimen for bilirubin testing arrives in the laboratory in a clear transport bag. The test is scheduled to be performed 2 hours after collection. What is the most likely issue with this specimen?

Answer: Bilirubin is light-sensitive and the specimen was not protected from light.

Bilirubin is a light-sensitive analyte. Exposure to light, especially ultraviolet light, causes it to break down, leading to falsely low test results. Specimens for bilirubin testing must be protected from light by using an amber-colored tube or by wrapping the tube in aluminum foil or other light-blocking material.

What is a type and screen versus a type and crossmatch?

Answer: Type and screen determines blood type and screens for antibodies; type and crossmatch additionally tests patient serum against a specific donor unit

A type and screen (group and screen) includes ABO/Rh typing and antibody screening. If a negative screen and no history of clinically significant antibodies exist, blood can be issued with an electronic (computer) crossmatch. A type and crossmatch includes the additional step of testing patient serum against a specific donor unit, required when clinically significant antibodies are present.

What action should be taken if a hematoma begins to form during venipuncture?

Answer: Immediately release the tourniquet, withdraw the needle, and apply firm pressure

Hematoma formation indicates blood is entering the tissue rather than the collection tube. The tourniquet must be released and needle withdrawn immediately, followed by firm pressure to prevent further extravasation.

In clinical chemistry, what is a 'blank' in the context of spectrophotometric analysis?

Answer: A solution containing all reagents but no analyte, used to zero the instrument

A blank (or reagent blank) contains all assay reagents but no analyte. It is used to zero the spectrophotometer, accounting for background absorbance from reagents and the cuvette.

What does proteinuria detected by dipstick primarily measure?

Answer: Primarily albumin (the indicator is more sensitive to albumin than other proteins)

The urine dipstick protein pad uses a pH indicator (tetrabromophenol blue) that is primarily sensitive to albumin due to the protein error of indicators principle. It may miss low-molecular-weight proteins like Bence Jones protein (immunoglobulin light chains). Sulfosalicylic acid (SSA) or total protein measurement detects all proteins.

Which serological test is used for the diagnosis of syphilis and what is the screening algorithm used in Canada?

Answer: Reverse algorithm: treponemal test (EIA/CIA) screen followed by RPR and confirmatory treponemal test

Many Canadian laboratories use the reverse syphilis screening algorithm: a treponemal-specific immunoassay (EIA or CIA) is used for screening, followed by RPR (a non-treponemal test to assess disease activity) and a second treponemal test (TP-PA or FTA-ABS) for confirmation. This approach has higher sensitivity for detecting latent syphilis.

An MLA/T is performing daily quality control (QC) on a point-of-care glucose meter. In addition to the daily requirement, in which of the following situations is it also mandatory to run QC?

Answer: When a new vial of test strips is opened.

Quality control must be performed on a point-of-care device not only on a scheduled basis (e.g., daily) but also whenever a new lot of reagents or supplies is introduced. Opening a new vial of test strips constitutes a change in reagents, and running QC verifies that the new strips are performing correctly with the meter. QC is also required if a device is dropped or if patient results are clinically unexpected.

What is the clinical significance of fibrin degradation products (FDPs) versus D-dimer?

Answer: FDPs detect degradation of both fibrinogen and fibrin; D-dimer is specific for cross-linked fibrin degradation

FDPs detect degradation products from both fibrinogen and fibrin, while D-dimer specifically detects fragments from cross-linked (Factor XIIIa-stabilized) fibrin. This means D-dimer is more specific for indicating that both clot formation and fibrinolysis have occurred, making it more useful for thromboembolism exclusion.

The administration of CPR on an adult requires how many chest compressions performed immediately before a series of two breaths is given?

Answer: 30

According to current CPR guidelines for adults, the recommended ratio of chest compressions to breaths is 30 compressions followed by 2 breaths. This sequence should be repeated until emergency medical services arrive or the person shows signs of recovery. Maintaining a compression rate of 100-120 compressions per minute is also crucial for effective CPR.

Which vein is considered the preferred primary site for adult venipuncture and why?

Answer: Median cubital vein — it is large, well-anchored, and has few nearby nerves and arteries

The median cubital vein is the preferred first-choice venipuncture site because it is typically large, well-supported by subcutaneous tissue, well-anchored, and relatively distant from major arteries and nerves.

What does the term 'evidence-based practice' mean for a medical laboratory technologist in Ontario?

Answer: Integrating the best available evidence from research with professional judgment and patient context to guide practice decisions

Evidence-based practice means integrating the best available research evidence with professional knowledge, experience, and the specific patient context to make optimal practice decisions.

Under Ontario's Personal Health Information Protection Act (PHIPA), which of the following is a primary responsibility of a 'health information custodian' such as a medical laboratory?

Answer: To collect, use, and disclose only the personal health information necessary for the purpose of providing care.

PHIPA operates on the principle of data minimization. Health information custodians, including laboratories, are legally obligated to collect, use, and disclose only the amount of personal health information that is reasonably necessary to provide the requested healthcare service. Sharing information requires consent or legal permission, not just a request from any provider. Storing photos is not a standard requirement, and record retention periods are governed by specific regulations and are much longer than one year.

A patient's urine shows many waxy casts, broad casts, and RTE cells. What does this suggest?

Answer: Severe chronic renal disease with tubular damage and stasis

Waxy casts indicate prolonged urinary stasis in damaged tubules. Broad casts ('renal failure casts') form in dilated, damaged collecting ducts. Renal tubular epithelial (RTE) cells indicate active tubular injury. Together, these findings suggest severe chronic kidney disease with ongoing tubular damage and a poor prognosis.

What is the Westgard rule 1₃s in quality control?

Answer: A rejection rule triggered when one QC result exceeds 3 SD

The 1₃s Westgard rule is a rejection rule: if a single quality control result exceeds the mean ± 3 standard deviations, the analytical run must be rejected.

A laboratory receives a synovial fluid specimen from a joint aspiration. Which finding on microscopic examination would confirm the diagnosis of gout?

Answer: Negatively birefringent needle-shaped crystals (monosodium urate) under polarized light microscopy

Gout is confirmed by the presence of negatively birefringent needle-shaped monosodium urate (MSU) crystals within or outside white blood cells under compensated polarized light microscopy.

Under Biosafety Level 2 (BSL-2) laboratory requirements in Canada, which personal protective equipment is mandatory when handling specimens suspected of containing bloodborne pathogens?

Answer: Gloves, laboratory coat, and eye protection

BSL-2 standard precautions require gloves, a laboratory coat or gown, and eye/face protection when handling potentially infectious bloodborne materials.

Which condition is associated with elevated serum phosphate and decreased calcium?

Answer: Chronic kidney disease

Chronic kidney disease causes hyperphosphatemia due to decreased renal phosphate excretion and hypocalcemia due to decreased vitamin D activation (1,25-dihydroxyvitamin D) by the diseased kidneys. This reciprocal relationship drives secondary hyperparathyroidism in CKD patients.