Which homogeneous LDL method feature avoids the Friedewald limit?

It measures LDL cholesterol directly

Glucose, HbA1c and lipid profile

55 Lab technician recruitment practice questions on Glucose, HbA1c and lipid profile, part of Clinical Biochemistry. The first 25 are below; the first 5 with answers and explanations (tap Show answer after you have chosen), the rest in Learn with a free account.

Question 1 · Easy
Triglyceride 1 mmol/L is equal to approximately:
1. A38.7 mg/dL
2. B100 mg/dL
3. C18 mg/dL
4. D88.5 mg/dL
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Answer: D · 88.5 mg/dL
Triglyceride results are converted using a mean molar mass of about 885 g/mol for triolein. So 1 mmol/L equals 88.5 mg/dL. Cholesterol uses 38.7 and glucose uses 18. The normal fasting limit of 150 mg/dL is about 1.7 mmol/L.
- A: 38.7 is the cholesterol conversion factor.
- B: 100 is not a conversion factor for triglyceride.
- C: 18 is the glucose conversion factor.
Question 2 · Easy
Glucose 1 mmol/L is equal to approximately:
1. A88.5 mg/dL
2. B38.7 mg/dL
3. C18 mg/dL
4. D10 mg/dL
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Answer: C · 18 mg/dL
The molar mass of glucose is 180 g/mol, so 1 mmol/L is 180 mg/L, or 18 mg/dL. To convert mg/dL to mmol/L, divide by 18. Thus 126 mg/dL is 7.0 mmol/L. The factor 38.7 applies to cholesterol and 88.5 to triglycerides.
- A: 88.5 is the conversion factor for triglycerides.
- B: 38.7 is the conversion factor for cholesterol.
- D: 10 is only the mg/L to mg/dL factor.
Question 3 · Easy
Which colour develops in the GOD-POD (Trinder) glucose reaction?
1. ARed-pink
2. BViolet
3. CBlue-green
4. DYellow
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Answer: A · Red-pink
Peroxidase couples 4-aminoantipyrine and phenol in the presence of hydrogen peroxide to form a red-pink quinoneimine. Its absorbance is read at about 505 nm. The intensity is proportional to the glucose in the sample. Blue-green colour belongs to the older o-toluidine method.
- B: Violet is the biuret protein colour.
- C: Blue-green is the o-toluidine glucose colour.
- D: Yellow is not the Trinder dye colour.
Question 4 · Medium
Which homogeneous LDL method feature avoids the Friedewald limit?
1. AIt measures LDL cholesterol directly
2. BIt ignores HDL
3. CIt uses fasting samples only
4. DIt needs no reagent
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Answer: A · It measures LDL cholesterol directly
Direct LDL assays use detergents or polymers to block other lipoproteins so only LDL cholesterol reacts. They work when triglycerides exceed 400 mg/dL. They do not need fasting samples. They are more costly than the calculation.
- B: Direct LDL does account for HDL by blocking it.
- C: Direct LDL works on non-fasting samples too.
- D: Direct LDL uses enzyme and detergent reagents.
Question 5 · Medium
A two-hour OGTT plasma glucose of 165 mg/dL with fasting 98 mg/dL indicates:
1. ADiabetes mellitus
2. BImpaired glucose tolerance
3. CNormal tolerance
4. DImpaired fasting glucose
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Answer: B · Impaired glucose tolerance
The fasting value of 98 mg/dL is normal. A two-hour value of 140-199 mg/dL is impaired glucose tolerance. Diabetes needs 200 mg/dL or more at two hours. Such patients are at risk and need lifestyle advice.
- A: Diabetes needs a two-hour value of 200 mg/dL or more.
- C: A normal two-hour value is below 140 mg/dL.
- D: The fasting value is normal, so this is not IFG.
Question 6 · Medium
Which HbA1c method separates haemoglobin fractions by charge and is widely used as a standardized method?
1. ABoronate affinity
2. BCation-exchange HPLC
3. CImmunoturbidimetry
4. DElectrophoresis on paper
Answer and explanation in LearnFree account
Question 7 · Hard
A diabetic has HbA1c 5.4% but fasting glucose readings of 180-220 mg/dL for months. HPLC shows an abnormal peak. The most likely cause is:
1. AA haemoglobin variant
2. BIron deficiency anaemia
3. CLipaemic sample
4. DRecent fasting
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Question 8 · Medium
In a woman screened for gestational diabetes by the DIPSI method used in India, glucose is measured:
1. AThree hours after 100 g
2. BOne hour after 50 g, fasting
3. CFasting only
4. DTwo hours after 75 g, regardless of fasting
Answer and explanation in LearnFree account
Question 9 · Medium
Lipaemic serum may cause a falsely high result in a colorimetric test because it:
1. AInhibits enzymes
2. BScatters light
3. CContains fluoride
4. DAbsorbs at 340 nm only
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Question 10 · Medium
In the CHOD-PAP method, a raised bilirubin causes which error?
1. AFalsely high cholesterol
2. BFalsely low cholesterol
3. CFalsely high HDL only
4. DNo error
Answer and explanation in LearnFree account
Question 11 · Medium
Why does a non-fasting sample affect calculated LDL more than total cholesterol?
1. AHDL falls after a meal
2. BLDL is made in the gut
3. CCholesterol is absorbed quickly
4. DTriglyceride rises after a meal
Answer and explanation in LearnFree account
Question 12 · Easy
Mutarotase is added to some glucose oxidase reagents to:
1. ARemove ascorbic acid
2. BStabilize the peroxidase
3. CInhibit red-cell glycolysis
4. DSpeed alpha-to-beta conversion
Answer and explanation in LearnFree account
Question 13 · Medium
A glucometer reading in a severely dehydrated patient with a high haematocrit is likely to be:
1. AFalsely low
2. BFalsely high
3. CUnreadable
4. DAccurate
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Question 14 · Medium
A random plasma glucose of 230 mg/dL in a patient with thirst and polyuria indicates:
1. ADiabetes mellitus
2. BImpaired glucose tolerance
3. CNeed for repeat HbA1c only
4. DNormal stress response
Answer and explanation in LearnFree account
Question 15 · Medium
Iron deficiency anaemia tends to affect HbA1c by:
1. AMaking it unmeasurable
2. BRaising it falsely
3. CHaving no effect
4. DLowering it falsely
Answer and explanation in LearnFree account
Question 16 · Medium
Which glucose test best monitors short-term control in a pregnant diabetic over the past three weeks?
1. AUrine glucose
2. BFasting glucose
3. CHbA1c
4. DFructosamine
Answer and explanation in LearnFree account
Question 17 · Easy
The enzyme in the cholesterol method that produces hydrogen peroxide is:
1. ACholesterol esterase
2. BCholesterol oxidase
3. CGlycerol kinase
4. DLipoprotein lipase
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Question 18 · Easy
In the GOD-POD method, glucose oxidase converts glucose into gluconic acid and:
1. ANADPH
2. BHydrogen peroxide
3. CCarbon dioxide
4. DLactic acid
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Question 19 · Medium
Why can freshly dissolved glucose read low by glucose oxidase without mutarotase?
1. AIt acts only on alpha-D-glucose
2. BIt needs NADP for alpha anomers
3. CIt needs phosphorylated glucose
4. DIt acts only on beta-D-glucose
Answer and explanation in LearnFree account
Question 20 · Medium
In an uncontrolled diabetic, which lipid pattern is most typical?
1. ALow cholesterol, low triglycerides
2. BLow triglycerides, high HDL
3. CHigh triglycerides, low HDL
4. DHigh HDL, low LDL
Answer and explanation in LearnFree account
Question 21 · Medium
A blood sample for lipid profile is drawn after a tourniquet has been on for five minutes. The most likely effect is:
1. ANo change in lipids
2. BFalsely low cholesterol
3. CFalsely high cholesterol
4. DFalsely low triglycerides
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Question 22 · Medium
In the o-toluidine glucose method, glucose reacts with o-toluidine in hot acetic acid to give:
1. AA purple complex
2. BA red quinoneimine
3. CA yellow osazone
4. DA blue-green glycosylamine
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Question 23 · Easy
HbA1c is formed by glucose binding to which part of haemoglobin?
1. AHaem iron
2. BN-terminal valine of beta chain
3. CLysine of gamma chain
4. DN-terminal valine of alpha chain
Answer and explanation in LearnFree account
Question 24 · Hard
Glucose on a busy ward sample from a leukaemia patient (WBC 150,000/µL) in a plain tube reads 40 mg/dL. The patient is alert and well. The first step is:
1. AReport critical hypoglycaemia at once
2. BRepeat on a promptly separated fluoride sample
3. CCheck the analyzer calibration
4. DRequest an HbA1c
Answer and explanation in LearnFree account
Question 25 · Medium
Why is a cholesterol test read against a reagent blank?
1. ATo dilute the sample
2. BTo correct for haemolysis
3. CTo subtract reagent colour
4. DTo warm the cuvette
Answer and explanation in LearnFree account

30 more Glucose, HbA1c and lipid profile questions

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Study Clinical Biochemistry

Glucose, HbA1c and lipid profile

Triglyceride 1 mmol/L is equal to approximately:

Glucose 1 mmol/L is equal to approximately:

Which colour develops in the GOD-POD (Trinder) glucose reaction?

Which homogeneous LDL method feature avoids the Friedewald limit?

A two-hour OGTT plasma glucose of 165 mg/dL with fasting 98 mg/dL indicates:

Which HbA1c method separates haemoglobin fractions by charge and is widely used as a standardized method?

A diabetic has HbA1c 5.4% but fasting glucose readings of 180-220 mg/dL for months. HPLC shows an abnormal peak. The most likely cause is:

In a woman screened for gestational diabetes by the DIPSI method used in India, glucose is measured:

Lipaemic serum may cause a falsely high result in a colorimetric test because it:

In the CHOD-PAP method, a raised bilirubin causes which error?

Why does a non-fasting sample affect calculated LDL more than total cholesterol?

Mutarotase is added to some glucose oxidase reagents to:

A glucometer reading in a severely dehydrated patient with a high haematocrit is likely to be:

A random plasma glucose of 230 mg/dL in a patient with thirst and polyuria indicates:

Iron deficiency anaemia tends to affect HbA1c by:

Which glucose test best monitors short-term control in a pregnant diabetic over the past three weeks?

The enzyme in the cholesterol method that produces hydrogen peroxide is:

In the GOD-POD method, glucose oxidase converts glucose into gluconic acid and:

Why can freshly dissolved glucose read low by glucose oxidase without mutarotase?

In an uncontrolled diabetic, which lipid pattern is most typical?

A blood sample for lipid profile is drawn after a tourniquet has been on for five minutes. The most likely effect is:

In the o-toluidine glucose method, glucose reacts with o-toluidine in hot acetic acid to give:

HbA1c is formed by glucose binding to which part of haemoglobin?

Glucose on a busy ward sample from a leukaemia patient (WBC 150,000/µL) in a plain tube reads 40 mg/dL. The patient is alert and well. The first step is:

Why is a cholesterol test read against a reagent blank?