Question 1

Normal adult glucose level (postprandial):

Accepted Answer

Answer reason: For most adults, a normal 2-hour postprandial (or post–oral glucose load) plasma glucose is below 140 mg/dL. Values from 140–199 mg/dL suggest impaired glucose tolerance (prediabetes), while 200 mg/dL or higher at 2 hours is consistent with diabetes when confirmed. The other options either reflect fasting targets (

Question 2

Incidence rate is defined as?

Accepted Answer

Answer reason: Incidence measures the occurrence of new cases developing in a population initially free of the condition, reflecting risk over a specified period. The denominator must be the population at risk (excluding existing cases when appropriate) and it is typically expressed per unit time (e.g., per year). Options including “new + old cases” describe prevalence, while mortality rate refers to deaths rather than new disease onset.
Category reason: This is an epidemiologic measurement definition used in interpreting screening and population health data, fitting Laboratory Values & Diagnostics rather than a nursing intervention scenario.

Question 3

Which is the best graphical representation for comparing proportions among categories?

Accepted Answer

Answer reason: Bar charts are designed to compare discrete categories and display their counts or proportions clearly side-by-side. Histograms are used for continuous numerical data grouped into bins, not categorical proportions. Line graphs best show trends over time or ordered sequences, and scatter plots show relationships between two quantitative variables. Therefore, the safest and most interpretable choice for comparing category proportions is a bar chart.
Category reason: This question tests selection of an appropriate data visualization method for comparing categorical proportions, which fits under interpretation/presentation of diagnostic or statistical data.

Question 4

A nurse is caring for a client with acute coronary syndrome. Which lab result is most concerning?

Accepted Answer

Answer reason: Troponin I is the most specific and sensitive biomarker for myocardial injury, and a value in this range is markedly elevated in the context of acute coronary syndrome. A low troponin (e.g., 0.01 ng/mL) is typically within or near the normal range and is less worrisome. Myoglobin can rise early but is nonspecific and may be elevated with skeletal muscle injury. A CK-MB of 2 ng/mL is generally not as concerning as a clearly elevated troponin because CK-MB is less specific and often lower in magnitude early or with smaller infarcts.
Category reason: This item tests interpretation of cardiac biomarkers and their diagnostic significance in acute coronary syndrome, which is primarily laboratory/diagnostic knowledge rather than a nursing intervention or prioritization decision.

Question 5

Under the National AIDS Control Program (NACP-IV), HIV testing strategy III is used for?

Accepted Answer

Answer reason: Strategy III in NACP-IV is intended for diagnosing HIV in asymptomatic individuals, using a sequential testing algorithm with multiple different assays to maximize diagnostic accuracy. Antenatal clients are often asymptomatic and require confirmatory diagnosis before interventions such as ART initiation and prevention of mother-to-child transmission services. In contrast, blood bank screening relies on highly sensitive single-assay screening (with confirmatory testing separately), and symptomatic/high-risk clinical settings (e.g., TB patients) typically follow diagnostic strategies tailored for symptomatic persons.
Category reason: This question tests knowledge of HIV testing algorithms under a national program, which is primarily about diagnostic testing strategy selection rather than nursing interventions, fitting Laboratory Values & Diagnostics.

Question 6

Normal partial thromboplastin time (PPT) is ?

Accepted Answer

Answer reason: b- 30-45 seconds This item tests knowledge of the normal range for the activated partial thromboplastin time (aPTT), which assesses the intrinsic and common coagulation pathways. Typical reference values are about 25–35 seconds in many labs, and 30–45 seconds is a commonly accepted normal range in exam settings. The 12–15 seconds range corresponds more closely to prothrombin time (PT), while minute-based options are not physiologic for standard coagulation assays.
Category reason: This question asks for a normal value of a coagulation laboratory test, which is foundational knowledge under Laboratory Values & Diagnostics rather than a nursing intervention or prioritization scenario.

Question 7

Which laboratory result is normal during pregnancy?

Accepted Answer

Answer reason: Physiologic leukocytosis is common in pregnancy due to hormonal influences and increased stress response, and values around 12,000/mm³ can be normal. A hemoglobin of 8 g/dL suggests significant anemia beyond typical hemodilution of pregnancy. A fasting glucose of 160 mg/dL is in the diabetic range and is not expected as a normal finding. Platelets of 80,000/mm³ indicates thrombocytopenia and is below the mild gestational thrombocytopenia range, raising concern for pathology.
Category reason: This item tests interpretation of expected physiologic changes in routine pregnancy lab values, which is best classified under Laboratory Values & Diagnostics rather than a nursing-intervention decision.

Question 8

Which of the following measures the strength of association between a risk factor and disease in a cohort study?

Accepted Answer

Answer reason: In a cohort study, participants are followed over time to compare the incidence of disease in exposed versus unexposed groups. The standard measure of the strength of association is the ratio of these incidences, which directly quantifies how much exposure changes risk. Odds ratio is primarily used in case-control studies, while attributable risk reflects excess risk due to exposure rather than the association ratio. Incidence rate is a frequency measure, not a comparative association metric by itself.
Category reason: This question tests epidemiologic/biostatistical measures used to interpret study results, which fits best under Laboratory Values & Diagnostics rather than nursing interventions or safety decisions.

Question 9

Sensitivity of a screening test is defined as?

Accepted Answer

Answer reason: Sensitivity measures how well a test identifies people who truly have the disease; it corresponds to the true-positive rate. Numerically it is calculated as TP/(TP+FN), so higher sensitivity means fewer false negatives. This is especially important for screening when missing a case would have significant harm, because a highly sensitive test helps rule out disease when negative.
Category reason: This question tests the definition of a diagnostic test performance characteristic (sensitivity), which is a core concept in interpreting laboratory/diagnostic screening tests.

Question 10

In a diagnostic test, if the prevalence of disease increases, the positive predictive value (PPV):

Accepted Answer

Answer reason: PPV is the probability that a person with a positive test truly has the disease, which depends on disease prevalence (pre-test probability) in the tested population. As prevalence rises, a greater proportion of positive results are true positives relative to false positives, increasing PPV (with sensitivity and specificity held constant). Conversely, higher prevalence decreases NPV, illustrating how predictive values shift with population risk rather than test characteristics.
Category reason: This item tests how disease prevalence affects predictive values (PPV), a core concept in interpreting diagnostic tests and screening performance, which fits Laboratory Values & Diagnostics rather than a patient-care intervention decision.

Question 11

A p-value of

Accepted Answer

Answer reason: A p-value < 0.05 means that, assuming the null hypothesis is true, the probability of observing results at least as extreme as those found is less than 5%. This meets a common threshold for rejecting the null hypothesis and calling the finding statistically significant. It does not prove the study is unbiased or that the result is true, and it does not indicate clinical importance, which depends on effect size and patient-centered outcomes.
Category reason: This question tests interpretation of a p-value (a statistical/diagnostic research metric), aligning best with understanding diagnostics and data interpretation rather than nursing interventions or prioritization.

Question 12

Westergren’s pipette is used for ?

Accepted Answer

Answer reason: The Westergren method specifically measures the erythrocyte sedimentation rate by allowing anticoagulated blood to stand in a standardized vertical tube and recording the distance RBCs fall in a set time. This device is calibrated for ESR and is not used for hematocrit, hemoglobin measurement, or leukocyte counting, which require different instruments and procedures. ESR is a nonspecific marker of inflammation and is reported in mm/hr.
Category reason: This question tests knowledge of a laboratory instrument and what diagnostic test it performs, which fits Laboratory Values & Diagnostics rather than nursing intervention decision-making.

Question 13

The venereal disease research laboratory test (VDRL) is done for diagnosis of?

Accepted Answer

Answer reason: VDRL is a non-treponemal serologic screening test that detects antibodies (reagin) produced in response to Treponema pallidum infection. It is used to screen for and help monitor treatment response in this condition, though confirmation is typically done with treponemal-specific tests. It is not a diagnostic test for gonorrhea (NAAT/culture), tuberculosis, or HIV/AIDS.
Category reason: This question tests knowledge of what a specific lab test (VDRL) is used to diagnose, which is best categorized under Laboratory Values & Diagnostics rather than nursing interventions or prioritization.

Question 14

The blood donor must not be less than:

Accepted Answer

Answer reason: b- 18 years Blood donation eligibility typically has a minimum age threshold to ensure the donor has reached physiologic maturity and can safely tolerate standard collection volumes. Many national blood services set the lower age limit at 18 years (sometimes 16–17 with parental consent depending on jurisdiction), making 18 the best general minimum among the choices. The other options set unnecessarily higher minimum ages and do not reflect standard eligibility criteria. Ensuring appropriate minimum age reduces risk of vasovagal reactions, anemia, and inadequate informed consent capacity.
Category reason: This is a factual question about eligibility criteria for blood donation, aligning with transfusion-related screening and diagnostic services rather than nursing care prioritization or interventions.

Question 15

205 - all of the following are diagnostic molecular biological technique except?

Accepted Answer

Answer reason: b- ELISA Molecular diagnostic techniques directly analyze nucleic acids (DNA/RNA) or their specific sequences. PCR, nucleic acid hybridization, and DNA fingerprinting all involve nucleic acid detection/amplification or pattern analysis. ELISA is an immunoassay that detects antigens or antibodies using enzyme-linked reagents, so it is not a molecular biology (nucleic-acid–based) diagnostic technique.
Category reason: This item tests classification of laboratory diagnostic methods (nucleic-acid–based vs immunoassay), which fits Laboratory Values & Diagnostics rather than nursing care decision-making.

Question 16

The reagent used for leukocyte count is ?

Accepted Answer

Answer reason: It is used in the leukocyte diluting fluid (e.g., Türk’s solution) to lyse red blood cells while preserving white blood cells for counting in a hemocytometer. This selective hemolysis clears the field and improves visibility of leukocytes. Other strong acids listed are not used for routine WBC diluents because they would not provide the appropriate selective RBC lysis/preservation needed for accurate counts.
Category reason: This question tests knowledge of a laboratory reagent used in performing a manual leukocyte count, which fits Laboratory Values & Diagnostics rather than clinical nursing decision-making.

Question 17

A client with cancer is admitted to the oncology unit. Stat lab values reveal Hgb 12.6, WBC 6500, K+ 3.1, uric acid 7.0, Na+ 136, and platelets 178,000. The nurse evaluates that the client is experiencing which of the following?

Accepted Answer

Answer reason: Serum potassium is critically interpreted against the normal range (~3.5–5.0 mEq/L), and a value of 3.1 indicates a true potassium deficit. The other provided labs do not support the distractors: sodium 136 is normal so hypernatremia is excluded, WBC 6500 is normal so leukocytosis is excluded, and platelets 178,000 with hemoglobin 12.6 do not indicate bone marrow suppression. Uric acid 7.0 may be mildly elevated but does not define any listed choice. Clinically, low potassium is the dominant abnormality and carries risk for muscle weakness and cardiac dysrhythmias, making it the best single interpretation.

Question 18

Quantity of sodium chloride required to make 1 litre of normal saline is?

Accepted Answer

Answer reason: Normal saline is a 0.9% w/v sodium chloride solution, meaning 0.9 g of NaCl per 100 mL of solution. Scaling to 1 litre (1000 mL) multiplies the amount by 10. This yields 9 g NaCl per litre, which matches the standard composition of 0.9% NaCl used in clinical practice. Options like 0.9 g reflect the amount per 100 mL rather than per litre, while 90 g is a tenfold overdose.

Question 19

Normal value of serum urea

Accepted Answer

Answer reason: a) 15-40mg/dl Urea (often reported as serum urea or BUN-related measure depending on lab) is used to assess renal excretory function and hydration status, with elevations seen in renal impairment, dehydration, and high protein catabolism. The commonly taught normal range for serum urea is approximately 15–40 mg/dL, matching the reference interval tested in many nursing/medical exams. The other ranges are either too narrow or shifted upward, which would incorrectly label many normal patients as abnormal. The last option is also internally inconsistent/likely a printing error, making it unreliable as a standard reference range.

Question 20

A client with cancer is admitted to the oncology unit. Stat lab values reveal Hgb 12.6, WBC 6500, K+ 1.9, urine 13.6, and platelets 178,000. The nurse evaluates that the client is experiencing which of the following?

Accepted Answer

Answer reason: B. Hypokalemia A serum potassium of 1.9 mEq/L indicates a critically low potassium level and is the most clinically significant abnormality in the values provided. Such severe depletion increases risk of life-threatening dysrhythmias, skeletal muscle weakness, and potential respiratory muscle compromise. The other listed labs (Hgb 12.6, WBC 6500, platelets 178,000) do not support bone marrow suppression or leukocytosis. Hyponatremia is not supported because the abnormal value shown is potassium rather than sodium.

Question 21

Which of the following conditions may warrant a serum creatinine level?

Accepted Answer

Answer reason: Serum creatinine is a key marker used to assess kidney function and detect acute or chronic impairment in glomerular filtration. Rhabdomyolysis can cause acute kidney injury from myoglobin-related tubular injury, so renal function monitoring with creatinine is essential. Digitalis (digoxin) is primarily renally cleared, and reduced renal function increases drug levels and toxicity risk, making creatinine important for interpretation and dosing decisions. Glomerulonephritis directly damages the glomeruli and can reduce filtration, so creatinine helps quantify the degree of renal impairment and track progression.

Question 22

Which is the normal bleeding time?

Accepted Answer

Answer reason: Bleeding time is a bedside screening test of primary hemostasis, reflecting platelet number/function and small-vessel integrity. The typical normal range taught for bleeding time is approximately 2–7 minutes, aligning with expected platelet plug formation. Shorter ranges such as 1–3 minutes are not the standard reference and risk missing mild platelet dysfunction. Markedly prolonged values like 8–15 or 15–20 minutes suggest impaired platelet function (e.g., aspirin effect, von Willebrand disease) or thrombocytopenia rather than normal physiology.

Question 23

Hypophosphatemia may result from which of the following diseases?

Accepted Answer

Answer reason: Chronic alcohol use is a classic cause of low serum phosphate due to poor nutritional intake, gastrointestinal losses, and impaired absorption. Alcohol-related malnutrition and refeeding after a binge or starvation period can also drive phosphate intracellularly, worsening hypophosphatemia. In contrast, renal failure more commonly leads to reduced phosphate excretion and hyperphosphatemia rather than low phosphate. Therefore, the option most directly associated with hypophosphatemia is alcohol use disorder.

Question 24

A patient with which of the following disorders is at high risk for developing hyperphosphatemia?

Accepted Answer

Answer reason: Phosphate and calcium have a reciprocal relationship in serum because elevated phosphate binds calcium and lowers free (ionized) calcium levels. Therefore, conditions characterized by low calcium are commonly associated with or can signal concurrent high phosphate, especially in settings like impaired renal excretion or tumor lysis physiology. This makes hypocalcemia a key laboratory accompaniment that raises suspicion for hyperphosphatemia. In contrast, isolated sodium, potassium, or glucose abnormalities do not directly predict phosphate retention or release.

Question 25

Normal calcium levels must be analyzed in relation to:

Accepted Answer

Answer reason: Serum calcium exists in different forms, with a large fraction bound to albumin in the blood. Because total calcium reflects both the free (ionized) and protein-bound portions, abnormal serum protein—especially low albumin—can make total calcium appear low even when the physiologically active ionized calcium is normal (pseudohypocalcemia). Therefore, interpreting a “normal” or “abnormal” total calcium value requires consideration of the patient’s protein/albumin level or use of corrected or ionized calcium. Glucose and fats do not determine calcium binding in the same clinically important way as albumin does.

Question 26

Scintigraphic examination of the kidneys with 99mTc - DTPA is?

Accepted Answer

Answer reason: 99mTc-DTPA is a radiotracer that is filtered by the glomeruli and is used to evaluate renal perfusion and glomerular filtration over time. Because the study assesses tracer uptake and excretion kinetics with time-activity curves (renogram), it is categorized as a functional, time-based (dynamic) renal scintigraphy. Static renal imaging is more characteristic of cortical-binding agents like 99mTc-DMSA for scarring and morphology rather than filtration dynamics. Whole-body imaging is not the standard application for this tracer when specifically assessing renal function.

Question 27

Which Test is done for detection of COVID-19?

Accepted Answer

Answer reason: Detection of active COVID-19 infection is best done by directly identifying viral genetic material in a respiratory specimen. RT-PCR amplifies SARS‑CoV‑2 RNA and is therefore a direct test of current infection, making it the standard diagnostic method for acute cases. Antibody tests primarily reflect prior exposure or later-stage immune response and can be negative early in infection, so they are not preferred for initial detection. Patch testing is used for allergic contact dermatitis and is unrelated to diagnosing viral respiratory infections.

Question 28

Which of the following are used in diagnosing breast cancer?

Accepted Answer

Answer reason: Mammography is the standard screening/initial diagnostic imaging test, ultrasound helps characterize masses and guide procedures (especially in dense breasts), and MRI is used for high-risk screening and assessing extent of disease. Definitive diagnosis requires biopsy to confirm malignancy on histopathology. Since each listed modality plays a valid role in diagnosing breast cancer, the best choice is the inclusive option.

Question 29

Investigation of choice for hydatid disease is?

Accepted Answer

Answer reason: g., daughter cysts, membranes). It also helps stage the cyst (WHO classification), which guides treatment decisions (observation vs albendazole vs PAIR vs surgery). CT can better define calcification or complex anatomy but is typically a second-line/complementary study rather than the first choice. Biopsy is avoided because cyst puncture can cause leakage with anaphylaxis and spread; serology such as ELISA supports the diagnosis but cannot reliably localize or stage disease on its own.

Question 30

EDTA is used for...?

Accepted Answer

Answer reason: EDTA is an anticoagulant that chelates calcium, preventing clot formation so whole blood cellular components remain intact for analysis. This makes it the standard additive in lavender-top tubes for hematology testing, including complete blood count and peripheral smear evaluation. Lipid profile and urea are typically chemistry analytes measured from serum or heparinized plasma rather than EDTA whole blood, and EDTA can interfere with some chemistry results. Therefore, the best match among the choices is the hematology test.

Question 31

Kaplan Meier method is for ?

Accepted Answer

Answer reason: g., lost to follow-up or event not yet occurred). It generates stepwise survival curves and allows comparison between groups (commonly via the log-rank test). Measures like prevalence and incidence describe disease burden or new case occurrence in a population, not time until an event. “Frequency” is too nonspecific and does not capture the core feature of censoring and time-to-event estimation.

Question 32

Cerebrospinal Fluid Contains all Except?

Accepted Answer

Answer reason: Red blood cells are not a normal constituent because the blood–brain barrier and intact meningeal vasculature prevent RBC entry into CSF. When RBCs are present, it typically indicates a traumatic lumbar puncture or intracranial bleeding such as subarachnoid hemorrhage. Compared with WBCs, which can be present in low counts and rise with infection/inflammation, RBCs should be absent in normal CSF.

Question 33

Normal level of Sodium in CSF in meq/L?

Accepted Answer

Answer reason: Typical reference values are around 138–150 mEq/L, making this value the best match among the choices. 112 mEq/L would indicate marked hyponatremia and would be clinically concerning rather than normal. 190 mEq/L is far above physiologic ranges and would not be compatible with normal CSF chemistry.

Question 34

The device used to produce X-rays is?

Accepted Answer

Answer reason: The x-ray tube is specifically designed to create this electron acceleration (cathode to anode) and convert kinetic energy into x-radiation (bremsstrahlung and characteristic radiation). The other devices listed are general electronic components or display instruments and do not produce ionizing radiation. Understanding the source of x-rays is fundamental for diagnostic imaging physics and radiation safety concepts.

Question 35

Orthotolidine test is used for detecting ?

Accepted Answer

Answer reason: This makes it useful for checking adequacy of chlorination in drinking water/public health settings. The other options do not cause the characteristic orthotolidine color change in routine use, and are detected by different chemical tests. Therefore, the test’s primary application is detection/estimation of chlorine residual.

Question 36

Osmolarity of normal saline is ?

Accepted Answer

Answer reason: 9% sodium chloride, meaning it contains 9 g NaCl per liter; with NaCl’s molecular weight ~58.5 g/mol, this equals about 0.154 mol/L. Because NaCl dissociates into two particles (Na+ and Cl−), this corresponds to ~154 mmol/L of sodium and ~154 mmol/L of chloride, making it isotonic with plasma. The question’s numeric choices are presented in mEq/L; the standard concentration of each ion in 0.9% NS is 154 mEq/L, which is why this value is the best match. Values like 144 or 134 mEq/L align more with normal serum sodium ranges rather than the composition of an IV solution.

Question 37

Elevated specific gravity can be seen in ?

Accepted Answer

Answer reason: With fluid volume deficit, ADH-mediated water reabsorption rises, reducing urine volume and increasing solute concentration, which elevates specific gravity. In contrast, diabetes insipidus typically causes inability to concentrate urine, producing very dilute urine with low specific gravity. Hypervolemia and many causes of polyuria more commonly produce relatively dilute urine, not an elevated value.

Question 38

Which cardiac marker raised first in myocardial infraction?

Accepted Answer

Answer reason: Myoglobin increases within about 1–2 hours after symptom onset, making it the earliest among the listed choices, but it is not cardiac-specific. CK-MB typically rises later (about 3–6 hours), and troponins rise around a similar timeframe but are preferred for diagnosis due to higher cardiac specificity and longer elevation. SGOT (AST) is nonspecific and rises later, so it is not the first marker.

Question 39

Which is the preservative used in 24 hrs urine collection ??

Accepted Answer

Answer reason: Toluene can form a surface layer that helps inhibit bacterial growth and reduces oxidation/evaporation effects for certain measurements. Acids such as acetic acid are used to acidify urine to stabilize acid-labile components and reduce microbial proliferation for specific ordered tests. Boric acid is also used as an antimicrobial preservative to maintain specimen integrity, so multiple preservatives may be appropriate depending on the analyte requested.

Question 40

ESR means

Accepted Answer

Answer reason: In inflammatory states, acute-phase proteins (especially fibrinogen) promote rouleaux formation, making red cells fall faster and increasing the measured rate. This definition matches the standard abbreviation used in clinical diagnostics. The other options confuse ESR with electrolytes or biosynthesis, which are unrelated to this sedimentation measurement.

Question 41

The reagent used for testing urine sugar is ?

Accepted Answer

Answer reason: This directly matches the purpose of “testing urine sugar” in basic clinical lab practice. Rothera’s reagent is used to detect ketone bodies (acetoacetate/acetone) in urine, not glucose. Sahli’s reagent is associated with hemoglobin estimation, making it unrelated to urine sugar testing.

Question 42

In hyperphosphatemia the electrolyte that needs to be provided is?

Accepted Answer

Answer reason: The key danger is functional hypocalcemia with neuromuscular irritability (e.g., tetany) and cardiac effects, so calcium replacement is the most direct corrective electrolyte when clinically indicated. In practice, management also includes lowering phosphate (dietary restriction, phosphate binders, dialysis in severe renal failure), but among the listed electrolytes the one to provide is calcium. Potassium, sodium, and magnesium do not directly counter the phosphate-calcium binding effect that produces the major acute physiologic consequences.

Question 43

What machine is used to test the blood?

Accepted Answer

Answer reason: This equipment is designed for diagnostic analysis (e.g., electrolytes, enzymes, CBC indices) using standardized reagents and detection systems. A hemodialyzer is used for renal replacement therapy to remove solutes and fluid from the bloodstream, not for laboratory testing. Diathermy machines deliver therapeutic heat, and ventilators support breathing, so neither is intended for blood analysis.

Question 44

Which test is done for identifying the presence of occult blood of stool ?

Accepted Answer

Answer reason: The guaiac-based fecal occult blood test (gFOBT) uses guaiac resin that changes color in the presence of heme and an oxidizing agent. This makes it a standard screening/diagnostic test for occult gastrointestinal bleeding. Fouchet's test is used for bile pigments (bilirubin), not occult blood, making it a clear distractor.

Question 45

Bilirubin in serum can be measured by..?

Accepted Answer

Answer reason: This approach also differentiates direct (conjugated, water-soluble) bilirubin from indirect (unconjugated) based on reaction conditions/accelerators. The other listed reactions are associated with different analytes or qualitative bile pigment testing rather than standard serum bilirubin quantification. Therefore, the best single test named for measuring serum bilirubin is the diazo-based method.

Question 46

Which of the following chemical is used to test urine for albumin?

Accepted Answer

Answer reason: Acetic acid is used as an acidifying reagent in classic heat-and-acetic-acid testing to confirm protein precipitation and help differentiate phosphates (which dissolve with acid) from true protein. Sodium nitroprusside is primarily used for ketone body detection rather than albumin. Ammonium sulfate is a protein “salting out” reagent used in lab fractionation, and liquor ammonia is not the standard reagent for urinary albumin testing.

Question 47

"Guthrie Test" is done in neonates for mass screening of?

Accepted Answer

Answer reason: Early identification is critical because untreated disease leads to irreversible neurocognitive impairment, while prompt dietary management prevents complications. This directly matches the purpose of the test as a mass-screening tool for inborn errors of amino acid metabolism. Other conditions listed are screened with different methods (e.g., TSH/T4 for congenital hypothyroidism; electrophoresis/HPLC for hemoglobin disorders).

Question 48

What is the normal pH range for arterial blood?

Accepted Answer

Answer reason: 7.35 to 7.45 Arterial blood is normally maintained within a very narrow pH window by the bicarbonate buffer system, lungs (CO2 elimination), and kidneys (H+ excretion/HCO3- regulation). Values below 7.35 indicate acidemia and values above 7.45 indicate alkalemia, so the normal reference range lies between these cutoffs. The broader range in option A includes clinically abnormal acidemia (e.g., pH 7.20–7.34) and alkalemia up to 7.49, so it is not a normal range. The higher ranges in options C and D describe alkalemic states rather than normal physiology.

Question 49

On collecting blood, what solution is added to it?

Accepted Answer

Answer reason: Citrate salts act as anticoagulants by binding ionized calcium, an essential cofactor in the coagulation cascade, thereby halting clot formation. Sodium citrate is the standard anticoagulant used in light-blue–top tubes for tests like PT/INR and aPTT because it provides reliable calcium chelation and can be reversed in the lab during testing. Phosphate salts are not used as routine anticoagulants for blood collection, and potassium citrate is not the standard additive in routine phlebotomy tubes compared with sodium citrate.

Question 50

Analysis of arterial blood gasses (ABGs) and oxymetry are the best methods to assess which of the following?

Accepted Answer

Answer reason: ABGs quantify arterial oxygen and carbon dioxide tensions (PaO2, PaCO2) and allow calculation of indices such as the A–a gradient, which reflect how well oxygen moves from alveoli into blood. Pulse oximetry complements this by estimating hemoglobin saturation (SpO2), providing a continuous, noninvasive marker of oxygen uptake. Together they best capture overall pulmonary gas exchange performance rather than a single isolated parameter. A common distractor is acid–base balance, which is assessed by ABGs but not by oximetry, making it a less complete match to the paired methods asked about.

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