Wednesday, June 28, 2017

ASPARTATE AMINOTRANSFERASE DETERMINATION Review Questions and Answers


1.    State the principle of the test.

AST in the serum catalyzes the transfer of an amino acid group to a keto acid group to form oxaloacetate and L-glutamate. This is measured spectrophotometrically at 505-535 nanometers.

2.    Name sources of error in this method.

Hemolyzed serum will increase values 10-15 X
Turbid, lipemic and icteric serum needs serum blanking for accuracy
Altered temperatures could either increase nor decrease values
Prolonged or shortened incubation time at specified conditions could increase or decrease values respectively

3.    What is the purpose of allowing the reagents to come to room temperature.

The purpose is to allow the reagents to inactivate the reagents so that they could react properly.

4.    Differentiate AST from ALT. Cite specific differences.

CRITERIA                     AST                                                      ALT
Substrate    L-aspartate & alpha-ketoglutarate            L-alanine & alpha-ketoglutarate
Old name    SGOT                                                       SGPT
One of the end products    oxaloacetate                       Pyruvate
Amount in inside serum    10-15 times                        5-8 times
Major clinical significance    heart                                Liver
       

5.    What is the component of the SGOT substrate?

L- aspartate and alpha-ketoglutarate



Sunday, June 25, 2017

Answers to Normality and Molarity Review Questions

Solving the Normality and Molarity of solutions is quite easy by remembering the relationship of Normality to Molarity.

1.    Normality may be equal but is always greater than the Molarity in the same solution.

2.    If the valence is 1, Normality is equal to Molarity.

Try solving these problems. Atomic weights: Na = 23; Cl = 35.5, H = 1, Ca = 40, Valences: Ca = 2, NaCl = 1, HCl = 1.

1.    If you have dissolved 20 grams of sodium chloride in 1.5 Liter of distilled water, what is the:
1.1.    Normality

You have to remember that Normality is the Gram Equivalent Weight of substances. Hence, valence is involved. The formula would be:

N = W/GEW/Liter of solution
GEW = W/MW/valence

So, you have to solve first the MW (sum of atomic weights);
MW = 23 (Na) + 35.5 (Cl) = 58.5

Thus, substituting the values: GEW = 20/58.5/1

GEW = 0.3418803

N = GEW/Liter of solution
N = 0.3418803/1.5
N = 0.2279202

Where:
N - Normality
W = weight of substance
GEW = Gram Equivalent Weight
MW = Molecular Weight
M = Molarity

1.2.    Molarity

Since you already know the Normality of the solution, you can make use of the short-cut formula, which is:

M = N/valence

Thus, substituting the values:

M = 0.2279202  x 1
M = 0.2279202

The answer is the same. This follows the rule: If the valence is 1, Normality is equivalent to Molarity.

1.3.    Percent solution

You don’t usually need the molecular weights when solving percent solutions. You could use the general formula:      

% = weight/total volume x 100

NOTE:

In solving for percent solutions, you have to convert the volume to milliliters. So,

1.5 Liters x 1000 mL/1 Liter = 1, 500 mL

Hence:
% = 20/1,500 x 100
% = 1.33333%

2.    What is the Molarity of 1 N Hydrochloric acid?
 
Again in this problem, since you know the Normality, make use of the short-cut formula:
      Thus:

    M = N/valence
    M = 1/1
    M = 1

Again: If the valence is 1, Normality is equivalent to Molarity.       

3.    What is the Normality of 0.8 M calcium chloride?

Use the short-cut formula:
N = M x valence
N = 0.8 x 2
N = 1.6


ALANINE AMINOTRANSFERASE (ALT) DETERMINATION Questions and Answers


1.    Discuss the principle of the method.

ALT in the serum catalyzes the transfer of an amino acid group to a keto acid group to form pyruvate and L-glutamate. This is measured spectrophotometrically at 505-535 nanometers.

2.    Aside from sodium hydroxide, what reagent could also be used to alkalinize the solution?

Potassium hydroxide

3.    Why should the distilled water used in dissolving your NaOH pellets be CO2 free?

Because carbon dioxide can affect the transfer of the amino group to the keto acid group due to its carbon content.  The carbon atom may act as an acceptor molecule in the reaction. This would falsely decrease your values.

4.    Why do we use a semi-log graphing paper in plotting your calibration curve?

Because the it is simpler to use since the graphing paper will find the logarithms of the values beforehand.


Saturday, June 24, 2017

How to Solve Normality and Molarity of Solutions

Solving the Normality and Molarity of solutions is quite easy by remembering the relationship of Normality to Molarity.

1.    Normality may be equal but is always greater than the Molarity in the same solution.

2.    If the valence is 1, Normality is equal  to Molarity.

Try solving these problems. Atomic weights: Na = 23; Cl = 35.5, H = 1, Ca = 40, Valences: Ca = 2, NaCl = 1, HCl = 1.

1.    If you have dissolved 20 grams of sodium chloride in 1.5 Liter of distilled water, what is the:

1.1.    Normality
1.2.    Molarity
1.3.    Percent solution

2.    What is the Molarity of 1 N Hydrochloric acid?

3.    What is the Normality of 0.8 M calcium chloride?

CLICK HERE FOR THE ANSWERS.


Friday, June 23, 2017

CLINICAL CHEMISTRY 2 DIAGNOSTIC QUIZ

MATCHING TYPE: 

MATCH COLUMN B WITH COLUMN A

COLUMN A (SUBSTANCE) 

1. GLUCOSE 
2. CHOLESTEROL 
3. TAG 
4. BUA
5. CREATININE 
6. BUN 
7. HDL 
8. TB H.
9. B1 
10. B2 

COLUMN B (CONVERSION FACTOR TO S.I.) 

A. 0.357
B. 0.113
C. 0.01128
D. 0.0258
E. 0.059
F. 0.0555
G. 0.1357
H..88.4
I. 0.555
J. 0.0359
K. 17.1


ESSAY:

1. DISCUSS THE PREPARATION OF ALKALINE PICRATE.

Monday, May 9, 2016

Answers to Thyroid Function Test, Case Analysis 4


CASE ANALYSIS 4

      AN APPARENTLY HEALTHY 33 YR-OLD WOMAN UNDERGOES THYROID TESTING WITH THE FOLLOWING RESULTS:  FT4 = 1.2 ng/dL, s-TSH = 15 uU/mL.  NO GOITER OR ANY OTHER ABNORMALITY IS NOTED.  THE PHYSICIAN IS CONCERNED, BUT DECIDES TO FOLLOW THE PATIENT FOR EVERY SIX MONTHS.  SIX MONTHS LATER THE PATIENT’S FT4= 1.1 ng/dL, s –TSH = 25 uU/mL.

QUESTIONS

      1.  WHAT CLINICAL STATE IS THE PATIENT APPARENTLY EXHIBITING? DEFEND YOUR ANSWER?

      Secondary or tertiary hypothyroidism.

      2.  WHY IS THERE CONCERN OVER THESE RESULTS?

      There may  be dysfunction in the anterior pituitary.

      3.  WHY WOULD MOST LABORATORY THYROID TESTS NOT BE USEFUL IN THIS CASE?

      Because the master gland is affected.

      4.  WHAT LABORATORY TEST WOULD BE USEFUL? WHY?

      Stimulation tests because it would determine what particular organ is dysfunctional.


Thyroid Function Test, Case Analysis


CASE ANALYSIS 4

      AN APPARENTLY HEALTHY 33 YR-OLD WOMAN UNDERGOES THYROID TESTING WITH THE FOLLOWING RESULTS:  FT4 = 1.2 ng/dL, s-TSH = 15 uU/mL.  NO GOITER OR ANY OTHER ABNORMALITY IS NOTED.  THE PHYSICIAN IS CONCERNED, BUT DECIDES TO FOLLOW THE PATIENT FOR EVERY SIX MONTHS.  SIX MONTHS LATER THE PATIENT’S FT4= 1.1 ng/dL, s –TSH = 25 uU/mL.

QUESTIONS

      1.  WHAT CLINICAL STATE IS THE PATIENT APPARENTLY EXHIBITING? DEFEND YOUR ANSWER?

      2.  WHY IS THERE CONCERN OVER THESE RESULTS?

      3.  WHY WOULD MOST LABORATORY THYROID TESTS NOT BE USEFUL IN THIS CASE?

      4.  WHAT LABORATORY TEST WOULD BE USEFUL? WHY?

CHECK ANSWERS HERE

Saturday, April 16, 2016

Answers to Thyroid Function Test (TFT), Case Analysis 3


CASE ANALYSIS 3

      A 59 YEAR OLD MAN WHO HAS BEEN DIAGNOSED WITH ACUTE RESPIRATORY DISTRESS SYNDROME SHOWED SYMPTOMS OF HYPOTHERMIA, COOLNESS IN THE EXTREMITIES, DECREASED BLOOD PRESSURE AND PULSE, FATIGUE, AND DELAY IN REFLEX TIME.  A THYROID PROFILE WAS ORDERED WITH THE FOLLOWING RESULTS:

LABORATORY FINDINGS

      FT4 = 4.0
      s.-TSH = 1.0 uU/mL

QUESTIONS

      1.  FROM THE CASE HISTORY AND THE LABORATORY DATA, WHAT IS A LIKELY DIAGNOSIS?

      Possibly euthyroidism or hypothyroidism, but since s-TSH is normal, it might be borderline case or a physiological factor is present.

      2.  WHAT ADDITIONAL LABORATORY TEST/S WOULD BE APPROPRIATE?

      FT3, TT3, Stimulation tests, TBG, or perform a delta check (repeat tests)

      3.  WHAT ADDITIONAL INFORMATION CONCERNING THE PATIENT WOULD BE HELPFUL IN INTERPRETING RESULTS?

      Patient’s history, surgical procedures done, drugs taken

      4.  IS TREATMENT FOR THYROID DISORDER INDICATED?

      Observe first for a few weeks and wait for additional tests and delta checks.


Thyroid Function Test TFT), Case Analysis 3


CASE ANALYSIS 3

      A 59 YEAR OLD MAN WHO HAS BEEN DIAGNOSED WITH ACUTE RESPIRATORY DISTRESS SYNDROME SHOWED SYMPTOMS OF HYPOTHERMIA, COOLNESS IN THE EXTREMITIES, DECREASED BLOOD PRESSURE AND PULSE, FATIGUE, AND DELAY IN REFLEX TIME.  A THYROID PROFILE WAS ORDERED WITH THE FOLLOWING RESULTS:

LABORATORY FINDINGS

      FT4 = 4.0
      s.-TSH = 1.0 uU/mL

QUESTIONS

      1.  FROM THE CASE HISTORY AND THE LABORATORY DATA, WHAT IS A LIKELY DIAGNOSIS?
 
      2.  WHAT ADDITIONAL LABORATORY TEST/S WOULD BE APPROPRIATE?
      3.  WHAT ADDITIONAL INFORMATION CONCERNING THE PATIENT WOULD BE HELPFUL IN INTERPRETING RESULTS?

      4.  IS TREATMENT FOR THYROID DISORDER INDICATED?


FOR TFT CASE ANALYSIS ANSWERS CLICK HERE.

Monday, April 11, 2016

Answers to Thyroid Function Case Analysis 2 - Questions


TFT CASE ANALYSIS 2

      1. A 41 YR OLD WOMAN COMPLAINED OF INCREASED SWEATING OVER THE PREVIOUS 3 MONTHS.  SHE ALSO STATED THAT SHE ALWAYS SEEMED NERVOUS AND HAD HEART PALPITATIONS AND HEAT INTOLERANCE.  SHE LOST 12 POUNDS OVER THE PAST 3 WEEKS AND HAD NONCRAMPING DIARRHEA.  ON EXAMINATION, HER SKIN WAS WARM AND MOIST, SHE HAD A PROMINENT STARE, AND SHE HAD TACHYCARDIA AT 140 BEATS PER MINUTE.  HER THYROID GLAND WAS DIFFUSELY ENLARGED WITH A SUGGESTION OF NODULARITY.

LABORATORY FINDINGS

      TT4 = 21.2 ug/dL ( 273 nmol/L)
      THBR RATIO = 2.0
      s-TSH = NONE DETECTED
      FT4I = 42.4 ng/dL ( 546 pmol/L)

QUESTIONS

      1. WHAT IS THE MOST PROBABLE CAUSE OF THESE SYMPTOMS AND LABORATORY RESULTS?

Hyperthyroidism with goiter

      2.  WHAT ADDITIONAL LABORATORY TESTING WOULD BE HELPFUL IN CONFIRMING THE DIAGNOSIS?

TT3 and FT3

      3.  WHAT IS THE SIGNIFICANCE OF THE s- TSH TEST?

It is the most sensitive test to confirm hypothyroidism or hyperthyroidism

      4.  WHAT CAUSES THE DISORDER?

Insufficient Iodine in the diet, dysfunctional thyroid gland


Chitika

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