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|Prompt=An experiment to measure the filtration fraction in healthy volunteers is conducted. One sample of the available urine and serum values is shown below. If the urine flow is 2.0 ml/min, what is the best approximate filtration fraction? | |Prompt=An experiment to measure the filtration fraction in healthy volunteers is conducted. One sample of the available urine and serum values is shown below. If the urine flow is 2.0 ml/min, what is the best approximate filtration fraction? | ||
[[Image:Screen Shot 2013-09-08 at 9.43.33 PM.png|600px | [[Image:Screen Shot 2013-09-08 at 9.43.33 PM.png|600px]] | ||
|Explanation=Despite the presence of several parameters, utilization of only [[creatinine]] and [[PAH]] is required to calculate the filtration fraction. | |Explanation=Despite the presence of several parameters, utilization of only [[creatinine]] and [[PAH]] is required to calculate the filtration fraction. | ||
Filtration fraction (FF) is calculated by the following equation: FF (%) = (GFR / RPF) x 100 | Filtration fraction (FF) is calculated by the following equation: FF (%) = (GFR / RPF) x 100 | ||
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|References=First Aid 2015 page 530 | |References=First Aid 2015 page 530 | ||
|RightAnswer=D | |RightAnswer=D | ||
|WBRKeyword=Renal physiology, Renal plasma flow, Filtration fraction, Nephrology, Kidney, GFR, PAH, Creatinine, | |WBRKeyword=Renal physiology, Renal plasma flow, Filtration fraction, Nephrology, Kidney, GFR, PAH, Creatinine, | ||
|Approved=Yes | |Approved=Yes | ||
}} | }} |
Revision as of 13:23, 6 August 2015
Author | [[PageAuthor::Rim Halaby, M.D. [1] (Reviewed by Will Gibson)]] |
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Exam Type | ExamType::USMLE Step 1 |
Main Category | MainCategory::Physiology |
Sub Category | SubCategory::Renal |
Prompt | [[Prompt::An experiment to measure the filtration fraction in healthy volunteers is conducted. One sample of the available urine and serum values is shown below. If the urine flow is 2.0 ml/min, what is the best approximate filtration fraction? |
Answer A | AnswerA::20% |
Answer A Explanation | AnswerAExp::One could obtain this number by using the ratio of the serum PAH to serum creatinine. However, this does not reflect any standard physiologic parameter. |
Answer B | AnswerB::30% |
Answer B Explanation | AnswerBExp::According to the calculation, this is an incorrect answer. |
Answer C | AnswerC::35% |
Answer C Explanation | AnswerCExp::According to the calculation, this is an incorrect answer. |
Answer D | AnswerD::40% |
Answer D Explanation | AnswerDExp::According to the calculation, this is a correct answer. |
Answer E | AnswerE::100% |
Answer E Explanation | AnswerEExp::This number could be achieved by dividing the renal creatinine concentration by the serum creatinine concentration. However, this measure does not reflect any normal physiologic parameter. |
Right Answer | RightAnswer::D |
Explanation | [[Explanation::Despite the presence of several parameters, utilization of only creatinine and PAH is required to calculate the filtration fraction.
Filtration fraction (FF) is calculated by the following equation: FF (%) = (GFR / RPF) x 100 GFR = (UCr x V)/PCr = (100 mg/dL x 2 ml/min ) / (1 mg/dL) = 200 mL/min RPF = (UPAH x V)/PPAH = (50 mg/dL x 2 ml/min ) / (0.2 mg/dL) = 500 mL/min FF (%) = (GFR / RPF) x 100 = (200/500) x 100 = 0.4 x 100 = 40% Abbreviations:
Educational Objective: The filtration fraction can be calculated by the following formula: FF (%) = (GFR/RPF) x 100 |
Approved | Approved::Yes |
Keyword | WBRKeyword::Renal physiology, WBRKeyword::Renal plasma flow, WBRKeyword::Filtration fraction, WBRKeyword::Nephrology, WBRKeyword::Kidney, WBRKeyword::GFR, WBRKeyword::PAH, WBRKeyword::Creatinine |
Linked Question | Linked:: |
Order in Linked Questions | LinkedOrder:: |