1. This is the gold standard for the glomerular filtration:

• A. urea clearance
• B. creatinine clearance
• C. inulin clearance ✅
• D. uric acid clearance

2. In order to accurately determine the GFR, a substance must meet the following criteria:

• 1. free glomerular filtration
• 2. no tubular absorption or secretion
• 3. inert
• 4. non toxic

• A. only 1 and 3 are correct
• B. only 2 and 4 are correct
• C. only 1,2, and 3 are correct
• D. 1,2,3 and 4 are correct
✅

3. Concerning glomerular filtration rate, which of the following statements is not true?

• A. In its early stage, type I diabetes mellitus results in a rise of the GRF as well as the renal plasma flow.
• B. Following donation of a kidney, the GFR in the organ donor stabilizes at 70-80% of the level prior to removal of the kidney.
• C. At the beginning of pregnancy the GRF decreases, by the end of the first trimester it is decreased by 20-30% ✅
• D. A protein challenge, an amino acid infusion or the administration of dopamine cause the GFR to rise.

4. Concerning an evaluation of renal function, the following laboratory investigations are correct for routine clinical diagnostic purposes:

• 1. serum creatinine; is elevated as of a GFR <50mL/min/1.73m2
• 2. serum urea; is elevated as of a GFR <30mL/min/1.73m2
• 3. serum beta-2-microglobulin; a concentration of <2.4mg/L indicates a normal or only slightly decreased GFR
• 4. serum cystatin C; the upper reference limit of healthy people is exceeded if the GFR is <80mL/min/1.73m2

• A. only 1 and 3 are correct
• B. only 2 and 4 are correct
• C. only 1,2, and 3 are correct
• D. 1,2,3 and 4 are correct
✅

5. The approved reference method for creatinine determination is the:

• A. isocratic HLPC
✅
• B. Fuller’s earth method
• C. Jaffe method
• D. Kinetic method

6. The low analytical specificity in creatinine determination is due to non-creatinine chromogens. Which of the following statements is true regarding non-creatinine chromogens?

• 1. Non-creatinine chromogens form a reaction product with alkaline picrate similar to that produced by creatinine.
• 2. During the early reaction phase, rapid reacting substances such as acetic acid contribute towards the color reaction.
• 3. During the middle phase reaction, the color reaction is almost exclusively due to creatinine.
• 4. During the late phase, glucose influence the color reaction.

• A. only 1 and 3 are correct
✅
• B. only 2 and 4 are correct
• C. only 1,2, and 3 are correct
• D. 1,2,3 and 4 are correct

7. In the enzymatic method for creatinine using phenol-aminophenazone peroxidase, creatinine is hydrolyzed to creatine by creatininase. In a further reaction step, both creatine produced from creatinine as well as endogenous creatine are degraded by creatinase into:

• 1. glycine
• 2. urea
• 3. H2O2
• 4. sarcosine

• A. only 1 and 3 are correct
• B. only 2 and 4 are correct
✅
• C. only 1,2, and 3 are correct
• D. 1,2,3 and 4 are correct

8. In uric acid methodology, the transformation of uric acid to allantoin and hydrogen peroxide by uricase in the presence of ambient air oxygen is used as the first reaction. For routine diagnostic purposes, which of the following enzymes are used to produce chromogen in the secondary reaction?

• 1. uricase-catalase reaction
• 2. aldehyde dehydrogenase
• 3. peroxidase
• 4. uricase

• A. only 1 and 3 are correct
• B. only 2 and 4 are correct
• C. only 1, 2, and 3 are correct ✅
• D. 1, 2, 3 and 4 are correct

9. By definition hyperuricemia is present if the serum uric acid concentration is > 6.5mg/dL. This definition is based on physico-chemical factors taking into consideration that the solubility of sodium urate at 37°C is:

• A. 6.4 mg/dL
✅
• B. 6.0 mg/dL
• C. 6.6 mg/dL
• D. 6.5 mg/dL

10. Which of the following substances may cause decreased levels due to inhibition of uricase?

• 1. citrate
• 2. oxalate
• 3. formaldehyde
• 4. oxalic acid

• A. only 1 and 3 are correct
• B. only 2 and 4 are correct
• C. only 1,2, and 3 are correct
• D. 1,2,3 and 4 are correct
✅

11. Which of the following statements regarding uric acid determination is correct?

• A. Blood collection can be performed even without fasting as long as it is done in the morning.
• B. Circadian rhythm does exist for the uric acid concentration, variations are dependent on time of the day.
• C. Blood collection performed after heavy muscular activity may result to a decrease in concentration
• D. After intensive sun exposure, blood collection may increase the result.
✅

12. The urea content of the blood is derived from the blood urea nitrogen level by multiplying the latter by a factor of:

• A. 0.46
• B. 2.14 ✅
• C. 0.64
• D. 2.41

13. These reagents are added to stabilize the color formed by the condensation of diacetyl with urea to form the chromogen diazine in the diacetyl monoxime method:

• 1. thiosemicarbazide
• 2. 2-oxoglutarate
• 3. Fe
• 4. ammonium heparinate

• A. only 1 and 3 are correct
✅
• B. only 2 and 4 are correct
• C. only 1,2, and 3 are correct
• D. 1,2,3 and 4 are correct

14. For the differentiation of renal acute renal failure from prerenal acute renal failure and postrenal acute renal failure, the urea/creatinine ratio can be used as a diagnostic criterion in addition to the clinical symptoms. Which of the following statements are correct when a normal protein intake of healthy people of approximately 1g/kg body weight/day is true?

• 1. 35, if both are determined in mmol/L
• 2. 25, if the determination is performed in mg/dL
• 3. 12, if urea is determined as BUN and if both are determined in mg/dL
• 4. 15, if urea is determined as BUN and if both are determined in mmol/L

• A. only 1 and 3 are correct
• B. only 2 and 4 are correct
• C. only 1,2, and 3 are correct ✅
• D. 1,2,3 and 4 are correct

15. The diacetyl monoxime method is relatively unspecific. Which of the following substances are measured as well?

• 1. creatinine
• 2. allantoin
• 3. arginine
• 4. glucose

• A. only 1 and 3 are correct
• B. only 2 and 4 are correct
• C. only 1,2, and 3 are correct ✅
• D. 1,2,3 and 4 are correct