glycosylated hgb nycocard Flashcards by MJ M

most abundant type of hemoglobin in human adults, making up 97% of total hemoglobin

Hemoglobin A

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components of Hemoglobin A

2 α-chains and 2 β-chains.

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types of glycated hemoglobins found in hemoglobin A1

A1a, A1b, A1c

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T/F Glycated hemoglobins migrate more rapidly than Hemoglobin A in an electric field.

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Glycosylated hemoglobin is formed in the body by the _____ of a sugar residue to the amino group of hemoglobin.

non-enzymatic addition

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Red blood cells with glucose attached, formed when glucose reacts with hemoglobin.

HbA1c

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T/F: The formation of glycosylated hemoglobin is irreversible and reflects blood glucose levels over the past 2 to 3 months.

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what percent of hemoglobin in the body is made up of Hemoglobin A2 and Hemoglobin F

Hemoglobin A2: 2.5%
Hemoglobin F: 0.5%

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rate of formation of glycosylated hemoglobin is directly proportional to ___

concentration of plasma glucose in the blood.

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The glucose molecule attaches non-enzymatically to hemoglobin, forming a ___ through a ___ base and then an ____ rearrangement to form HbA1c

ketoamine, Schiff, Amadori

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HbA1c provides a time-averaged picture of the patient’s blood glucose concentration over the past ___ months

2-3

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T/F: HbA1c is more reliable for long-term diabetes control monitoring than random plasma glucose.

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Odd One Out: Formation of HbA1c
A) Glucose condensation
B) Schiff base formation
C) Enzymatic reaction
D) Amadori rearrangement

C) Enzymatic reaction – formation of HbA1c is non-enzymatic.

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major fraction of glycated hemoglobin and its proportion of total HbA1

HbA1c - 80% of HbA1.

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T/F Glycation may also occur at other sites on the hemoglobin molecule, such as lysine residues or on the alpha chains.

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How is total glycated hemoglobin measured in lab

boronate affinity chromatography

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decreased red blood cell lifespan results in ___ glycosylated hemoglobin levels because the hemoglobin has less time to become glycosylated.

decreased

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T/F The rate of formation of glycosylated hemoglobin is directly proportional to the concentration of glucose in the blood.

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How often does the ADA recommend HbA1c testing for patients who are meeting treatment goals and have stable glycemic control

2x a yr

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How often should HbA1c be tested for patients who are not meeting glycemic goals or whose therapy has changed?

quarterly

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target HbA1c level recommended for non-pregnant adults to reduce the risk of complications

<7%

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Which of the following complications is NOT reduced by lowering HbA1c to less than 7%?
A) Microvascular complications
B) Retinopathy
C) Hypoglycemia
D) Neuropathy

C) Hypoglycemia – Hypoglycemia is not a complication reduced by lowering HbA1c

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goal HbA1c level goal for selected individual patient without significant hypoglycemia

lowering HbA1c to <6%

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what amino acid is glucose’s favorite landing site

N-terminal Valine

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glycated hemoglobin measurement method uses polyclonal or monoclonal antibodies targeted toward the glycated N-terminal group of the β-chain of hemoglobin

Immunoassays

separates based on chemical structure using borate to bind glycosylated proteins.

Affinity Chromatography

Odd One Out: Based on structural differences A) Immunoassays B) Affinity Chromatography C) Electrophoresis D) None of the above

C) Electrophoresis – based on charge differences.

type of chromatography separates glycated hemoglobin based on charge differences using a positive-charge resin bed

Ion-exchange chromatography

method of glycated hemoglobin measurement that is temperature dependent and affected by hemoglobinopathies

Ion-exchange chromatography

T/F: Electrophoresis separates hemoglobin based on charge differences and can be affected when Hemoglobin F values are greater than 7%.

gold standard for identifying glycated hemoglobin

High-pressure liquid chromatography (HPLC)

T/F: Isoelectric focusing is a form of electrophoresis that uses the isoelectric point to separate glycated hemoglobin.

Odd One Out: Charge differences A) High-pressure liquid chromatography (HPLC) B) Isoelectric focusing C) Affinity chromatography D) Ion-exchange chromatography

C) Affinity chromatography – separates based on chemical structure

type of sample required for HbA1c testing

EDTA whole blood

T/F Patients need to be in a fasting state for HbA1c testing.

F -- do not need to fast

How long can whole blood samples for HbA1c testing be stored at 4°C?

1 wk

what temperature are whole blood samples not stable for HbA1c testing?

-20°C

Odd One Out: Storage conditions for stable HbA1c testing samples A) 4°C for up to 1 week B) -70°C or colder for at least 18 months C) -20°C D) 2-8°C for up to 1 week (NycoCard recommendation)

C) -20°C – Samples are not stable at -20°C.

in vitro diagnostic test for the quantitative determination of glycated hemoglobin (HbA1c).

NycoCard System

T/F NycoCard READER II is a reflectometer that measures light reflected from the test sample relative to a white sample

type of light is used in the NycoCard READER II to measure glycated hemoglobin

Light-emitting diodes (LEDs), with three pairs of LEDs (blue, red, and green).

How does the NycoCard READER II measure reflected light from the test sample?

using a photodiode circuit relative to a white sample

T/F NycoCard System can help identify patients at risk for developing diabetes.

test time for the NycoCard HbA1c test

3 minutes

sample volume required for the NycoCard HbA1c test

5 μL

HbA1c measuring range for the NycoCard HbA1c test

4%–15%

test principle used by the NycoCard HbA1c to separate and quantify glycated and non-glycated hemoglobin

Boronic acid affinity

T/F: The NycoCard HbA1c test is affected by common Hb variants.

F - not affected

Odd One Out: Feature of the NycoCard HbA1c test A) Batch testing capability B) 3-minute test time C) 5 μL sample volume D) Certified by NGSP and IFCC

A) Batch testing capability – designed for small test series only; cannot do batch testing

How many tests can be performed with the NycoCard HbA1c Kit?

24 tests

purpose of Reagent 2 (R2) in the NycoCard HbA1c test

removes free conjugate from the top of the membrane

purpose of the test device (TD) in the NycoCard HbA1c test

separates precipitated hemoglobin from liquid and other cell components

How long is the HbA1c control stable after opening when stored at refrigerated temperature (2-8°C)?

30 days

T/F: Before use, all reagents in the NycoCard HbA1c Kit should be kept at frozen temperature and shaken vigorously for a minimum of 15 seconds.

F -- room temperature; 10 secs

steps of NycoCard HbA1c assay test procedure

A) Dilute and lyse the sample B) Apply sample to test device C) Apply washing solution D) Read the result

first step in the NycoCard HbA1c assay test procedure

Dilute and lyse the sample by applying 5 μL of sample to a tube with R1 (reagent) and mixing well.

How long should the sample incubate in the NycoCard HbA1c test during step 1?

2-3 mins

Odd One Out: Part of the NycoCard HbA1c assay test procedure A) Dilute and lyse the sample B) Apply sample to test device C) Heat the sample at 37°C D) Apply washing solution

C) Heat the sample at 37°C - sample is not heated in the NycoCard HbA1c test.

volume of the sample mixture is applied to the test device (TD) in the second step of the NycoCard HbA1c test

25 μL

T/F: After applying the washing solution to the test device, you must allow the solution to soak completely into the membrane before proceeding.

How should the test result be read in the NycoCard HbA1c test?

Place the test device on the NycoCard READER II pad and read the result within 5 minutes.

Steps to Operate the Nycocard Reader II

1. Adjusting 2. White Calibration 3. Measure a Test

first step to operate the NycoCard READER II

Adjusting – Ensure pen is in the penholder and turn the NycoCard READER II on for automatic black calibration

T/F: You should always perform white calibration when turning the NycoCard READER II back on.

Which of the following should NOT be done during NycoCard READER II operation? A) Discard the test device after use B) Perform white calibration when turning the device on C) Measure results without the NycoCard READER II pad D) Read the results within 5 minutes

C) Measure results without the NycoCard READER II pad – may lead to incorrect results.

Why must the NycoCard HbA1c test result be read within 5 minutes?

Stable hemoglobin precipitate on the membrane during 5 mins is the one being measured.

T/F After 5 minutes, the membrane becomes too dry, which can lead to inaccurate results in NycoCard HbA1c test

What is the NycoCard HbA1c test principle based on?

Boronic acid affinity, which binds to the cis-diol configuration of glycated hemoglobin.

T/F The ratio of blue and red color intensities measured by the NycoCard READER II is proportional to the percentage of HbA1c in the blood sample

What happens when hemoglobin precipitates in the NycoCard HbA1c test?

The boronic acid conjugate binds to the cis-diol configuration of glycated hemoglobin.

In the NycoCard HbA1c test, what does the blue color intensity correlate to?

concentration of glycated hemoglobin, measured using red LED.

what does red color intensity correlate to in the NycoCard HbA1c test

concentration of total hemoglobin (glycated and non-glycated), measured using blue LED.

Odd One Out: Steps in NycoCard HbA1c test procedure A) Lysis of red blood cells B) Precipitation of hemoglobin C) Addition of glucose to the sample D) Washing away excess conjugate

C) Addition of glucose to the sample – Glucose is not added to the sample in the NycoCard HbA1c test

What happens to the reaction mixture in the NycoCard HbA1c test after applying it to the test device?

All precipitated hemoglobin (glycated and non-glycated) remains on the membrane.

removes excess conjugate from the membrane in the NycoCard HbA1c test

washing reagent (R2)

T/F: In the NycoCard HbA1c test, blue intensity is measured using red LED, and red intensity is measured using blue LED.

formula used to calculate %HbA1c based on color intensity

%HbA1c= blue / red

ratio used to calculate %HbA1c based on hemoglobin concentrations?

%HbA1c= Total glycated hemoglobin/Total hemoglobin

HbA1c level recommended for diabetic patients according to the ADA

<7.0%

T/F incidence of retinopathy increases in patients with an HbA1c level between 6.0% and 7.0%

Odd One Out: Recommended frequency for HbA1c testing A) Twice a year for controlled patients B) Every quarter for uncontrolled patients C) Once a month for all patients

C) Once a month for all patients – HbA1c should be checked twice a year if controlled and quarterly if uncontrolled.

ideal HbA1c level to reduce the chance of retinopathy, according to the ADA

< 6.5%

How often should HbA1c be checked in diabetic patients with controlled blood sugar levels?

twice a year

HbA1c levels above 6.5% are indicative of ?

Diabetes mellitus

T/F: Hemolytic anemia and sickle cell trait can result in lower HbA1c levels due to the shorter lifespan of red blood cells.

Why do conditions like pregnancy and iron deficiency affect HbA1c test results?

cause anemia, leading to lower HbA1c levels.

Odd One Out: Lower HbA1c levels A) Pregnancy B) Iron deficiency C) Polycythemia D) Hemolytic anemia

C) Polycythemia – increases oxygen concentration and can result in higher HbA1c levels.

acceptable hemoglobin concentration range for a sample used in the HbA1c test

6.0 g/dL - 20.0 g/dL

Why is polycythemia associated with higher HbA1c levels?

increases the concentration of oxygen, resulting in higher total hemoglobin and thus higher HbA1c levels.

How does blood loss impact HbA1c levels?

lower HbA1c levels because of the reduced lifespan of red blood cells

True or False: Diluted samples can be used in the HbA1c test if properly handled.

F - Diluted samples cannot be used in the HbA1c test.