Test 2 Flashcards
What is the normal glucose concentration of serum?
80-100 mg%
What are some of the requirements that must be adhered to during an oral GTT?
Patient cannot smoke
Fasting at least 10 hours, not more than 16 hours
Done in the morning
Refrain from eating, drinking, smoking, exercise
List the order of mobility of serum proteins during an electrophoresis.
- Most rapid: Albumin
- Slowest: Gamma globulin
Order:
Albumin - Alpha 1 - Alpha 2- Beta fractions - Gamma
Why can the biuret method NOT be used for determining CSF or urine protein?
Lacks sensitivity. Cannot detect low concentrations of protein.
What does the biuret reagent specifically react with?
Tripeptides or larger.
What is the reference method for total protein determination?
Kjeldahl
Which method for measuring albumin is most commonly used in automated instruments?
Dye binding method
What SPE abnormality is seen in multiple myeloma?
Gamma globulin (increased)
What SPE abnormality is seen in nephrotic syndrome?
Alpha 2 globulin (increased)
Glucose in CSF is approximately ______ of the amount of glucose in the blood.
2/3
In bacterial meningitis, what would be the expected results for CSF protein and CSF glucose?
Protein - Increased
Glucose - Decreased
What anticoagulant is used to prevent glycolysis?
Sodium fluoride (gray top tube)
ACTH
Increases blood glucose levels.
Glucagon:
Increases blood glucose levels.
Glucocorticoids:
Increases blood glucose levels.
Insulin:
Decreases blood glucose levels.
Epinepherine:
Increases blood glucose levels.
What is the action of the enzyme glucose-6-phosphate dehydrogenase?
Removes hydrogen from glucose-6-phosphate, gives it to NAPD.
What technique is used to identify patients with familial hyperlipoproteinemia?
Electrophoresis
What are the normal values for albumin, globulin, and total protein?
Albumin: 3.8 - 4.7
Globulin: 2.3 - 3.5
Total Protein: 6 - 8
What phenomenon causes the gamma globulins to move towards the cathode in SPE, even though they are negatively charged?
Electroendosmosis (EEO)
What specific form of hemoglobin is used to monitor patients with Type I diabetes mellitus?
A1C
How is globulin in serum routinely determined?
total protein (minus) albumin
Which fraction of lipoprotein contains the highest percent of protein?
HDL
What is the order of migration, beginning at the origin, of lipoproteins?
Chylomicrons - prebeta - beta - alpha
What is the desirable level of total cholesterol in the serum?
less than 200 mg
What would be the most likely explanation if a patient’s laboratory results indicated elevated total cholesterol and triglyceride levels but a normal lipoprotein pattern?
Patient is not fasting.
Also, possible 2x draw - fasting for lipoproteins, not fasting for other Chemistry results.
Which lipoprotein fraction is responsible for post-prandial lipemia?
Chylomicrons
If plasma is used instead of serum for electrophoresis, what change will be observed?
Fibrinogen creates an extra fraction in beta gamma region. (Aka: M-Spike)
What dyes can be sued for the detection of albumin?
Bromcresol green (BCG), bromcresol purple, bromcresol orange, PABA.
What is considered to be the desirable level of HDL?
> /= 40
What is the value for a normal two-hour post-prandial glucose?
less than 140
In a normal glucose tolerance curve, the plasma glucose level returns to a normal fasting level in ____ hours.
3 hours (180 mins)
Name four blood constituents that can produce a falsely decreased cholesterol level due to interference with the enzymatic cholesterol assay.
Uric acid
Ascorbic acid
Bilirubin
Gludathion
What is the electrophoresis classification of the following lipoproteins:
HDL - alpha
LDL - beta (bad cholesterol, 2/3 of plasma cholesterol)
VLDL - prebeta
Which lipoprotein has a protective effect against coronary artery disease?
HDL
A protein isolated from a lipoprotein which is also affiliated with certain lipoproteins is referred to as an
Apoproteins
Interpret the GTT results for the following:
- Diabetes mellitus: elevated after 3 hours. Start high, stay high, take longer to return to normal.
- Hypoglycemia: lower than normal after 3 hours. Normal, then falls to below fasting levels.
- Normal: elevates at 1hr starts to decrease by 2 then return to normal fasting levels in 3 hours
Why is the performance of electrophoresis on CSF more difficult than SPE?
Protein concentration is low. Concentrate it 100x.
Patients with borderline blood glucose levels are most often further tested by preforming a
3 hour Oral GTT
What is actually measured in the hexokinase method for glucose?
NADPH
What is the normal range for spinal fluid glucose?
2/3 plasma or 40-70 mg/dL
What period of fasting is required for patients for whom the doctor has ordered lipid panels?
12 hours minimum
What is the reaction that takes place during the biuret procedure?
Copper reduction (purple color)
What precautions must be taken prior to collecting a specimen for lipid analysis?
12 hrs fasting - 2 week normal diet - no medications that affect lipids - defer 2 months after surgery, AMI, or serious illness
What is the main function of lipoproteins in the body?
Transport of body lipids throughout bloodstream.
What is most specific method for determining plasma cholesterol?
Cholesterol oxidase enzymatic reaction.
What protein, when found in increased amounts, lowers the risk of coronary heart disease?
Apoprotein A1
What is the only diagnostic purpose for performing a phospholipid measurement?
Nieman Pick Disease
What unusual electrophoretic serum protein pattern is seen in cirrhosis of the liver?
Beta gamma bridge
What would be the expected shape of a GTT curve if the patient has malabsorption syndrome?
No change in curve (nothing absorbed) - resulting in a flatline.
To resolve: IV GTT test instead.
What test may be used to asses the average plasma glucose level that a patient has maintained during a previous 2-3 month period?
Glycosulated Hemoglobin (to which A1C belongs)
The enzyme that causes the release of H2O2 when it reacts with glucose is
Glucose oxidase
What would happen to the glucose in a blood specimen if it was drawn in a clot tube and was left uncentrifuged at room temperature?
Decrease by 7 mg/dL per hour
The amount of glucose which is used in an adult GTT is
75g
What reagent is used for color development in the Libermann-Buchard reaction?
Combination of acetic anhydride and sulfuric acid
What adjustment is made to an OGTT if hypoglycemia is suspected?
Additional 4-5 hours of testing
B-lipoproteins contain high % of ________ while pre-B-lipoproteins contain a high % of ________
- Cholesterol
- Triglycerides
How would a physician view the prognosis of a patient with an elevated HDL level?
Good, not at a high risk. Patient protected from arthrosclerosis.
What is the most likely explanation of a milky serum?
Increased chylomicrons
What enzyme catalyzes the hydrolysis of triglycerides?
Lipase
What is the normal range for spinal fluid protein?
15 - 45
What compound is used to stimulate the pancreas to produce insulin?
Tolbudamide.
Why? Detection of insulinomas.
Ultracentrifugation separates lipoproteins into various categories based on the physical property if
Density
What stains can be used to stain the protein bands obtained from SPE?
Ponceau S
Amino Black 10 B
Bromphenol blue
Lissamine green
At what pH is routine SPE performed?
8.6
What is gestational diabetes?
Diabetes during pregnancy
What is meant by the term renal threshold? What is the renal threshold for glucose?
glucose levels in the blood above which glucose spills over into the urine
160-180 mg/dL
What type of diabetes occurs in adults?
Type 2
Name a test that can be used to determine the risk of RDS in newborns?
Phospholipid test
-L/S ratio
