Quantification of Renal Function

Glomerular filtration rate

This is the volume of plasma that is filtered across the glomerulus per unit time and can be quantified with both endogenous and exogenous molecules.

Inulin

This is the common exogenous molecule used to quantify and estimate renal function because 100% of this molecule given will be excreted by the kidneys. The clearance ratio of this molecule can determine if active secretion or reabsorption is occurring.

Reabsorbed

If the ratio of cleared inulin to administered amount of inulin is less than 1, it shows that inulin is actively ________

Filtered

If the ratio of cleared inulin to administered amount of inulin is equal to 1, it shows that inulin is _______

Secreted

If the ratio of cleared inulin to administered amount of inulin is greater than 1, it shows that inulin is actively _______

Exogenous

There are concerns with the use of _____ molecules to estimate renal function because these molecules are expensive, difficult to obtain due to a limited amount produced at a certain time, and requires specially trained, technical laboratory experience for a tech to be able to properly synthesize these molecules.

Creatinine

The advantages of using ______ to quantify renal function is that these endogenous molecules are routinely available, healthcare professionals have a degree of familiarity with what _______ is, and standard assays to measure the amount of ________ exists.

Secretion

A disadvantage of using creatinine to quantify renal function is that this molecule has a degree of tubular ________ into the lumen because creatinine is naturally synthesized by the body.

Muscle mass

A disadvantage of using creatinine to quantify renal function is that it may falsely elevate or reduce serum creatinine because it is proportional to the ______ of a patient.

Cystatin C

The advantage of using ______ to quantify renal function is that it is not affected by the muscle mass that a patient has.

Cystatin C

The advantage of using _______ instead of creatinine to quantify renal function is that it elevates faster than creatinine. Creatinine only shows changes 24-48 hours after the event whereas _______ is able to provide an elevation faster in the case of an acute kidney injury.

Cystatin C

The disadvantage of using ________ to quantify renal function is that it undergoes renal metabolism, is affected by smoking habits and thyroid conditions that may affect its concentration.

Creatinine

This is the most commonly used endogenous molecule where elevations come from muscle production and impaired excretion by the kidneys.

Increase

If a patient uses Cimetidine, which is a H2 antagonist, it will ______ serum creatinine

Increase

If a patient has a higher consumption of animal protein or is dehydrated, it will _______ serum creatinine

Increase

If a patient has a larger muscle mass, it will _________ serum creatinine compared to a patient who has less muscle mass.

Decrease

If a patient is paralyzed, elderly, had an amputation or has decreased muscle mass, these factors result in a ________ in serum creatinine.

Decrease

When levels of Cystatin C or creatinine increases, this will _______ renal clearance, which means that kidney function is worsening.

Increase

Blood urea nitrogen is a molecule that is associated with renal function where it is a product of protein metabolism. If a patient is experiencing a GI bleed, it will ______ BUN levels

Increase

Blood urea nitrogen is a molecule that is associated with renal function where it is a product of protein metabolism. If a patient is experiencing dehydration, acute kidney injury or has chronic kidney disease, it will ______ BUN levels

20:1

If the ratio of BUN to serum creatinine is greater than ________, it signifies that the patient may be dehydrated or have an acute kidney injury or chronic kidney disease.

Increase

Blood urea nitrogen is a molecule that is associated with renal function where it is a product of protein metabolism. If a patient is eating a high protein diet, it will _____ BUN levels.

Decrease

Blood urea nitrogen is a molecule that is associated with renal function where it is a product of protein metabolism. If a patient is experiencing starvation or is eating a diet low in solutes, it will ______ BUN levels.

Decrease

Blood urea nitrogen is a molecule that is associated with renal function where it is a product of protein metabolism. If a patient has severe liver disease, it will ______ BUN levels

MDRD

This equation of estimating renal function is largely outdated because it contains a racial component to the equation and often times end up overestimating renal function

CKD-EPI

If asked to estimate renal function using either the MDRD or CKD-EPI equation, which is preferred over the other equation?

Proteins

If a patient's urinalysis has ________ present, it may indicate that the patient has kidney disease

Glucose

If a patient's urinalysis has ______ present, it may indicate that a patient's blood sugar values are inadequately controlled.

White blood cells

If a patient's urinalysis has _______ present, it may indicate that a patient has a potential infection.

Red blood cells

If a patient's urinalysis has ______ present, it may indicate that a patient has potential structural damage

Low

If a patient's urinalysis has _____ specific gravity, it may indicate that the patient has dilute urine.

High

If a patient's urinalysis has ______ specific gravity, it may indicate that the patient has concentrated urine.

A1

This category of proteinuria indicates a normal to mildly increased level of protein in the urine.

A2

This category of proteinuria indicates a moderately increased level of protein in the urine.

A3

This category of proteinuria indicates a severely increased level of protein in the urine.

Proximal convoluted tubule

Glucose should normally not be present in the urine as it is mainly reabsorbed in the ________ of the nephron.

180 mg/dL

What is the threshold of glucose reabsorption where any levels higher than this threshold may result in the presence of glucose in the urine?

SGLT-2 inhibitors

This class of medications has a common adverse effect of the presence of glucose in the urine because these medications inhibit the sodium-glucose transporter in the proximal convoluted tubule and this results in glucose not being reabsorbed and being secreted with the filtrate.

Dysmorphic

If urine microscopy shows ______ red blood cells, this may be indication of other kidney diseases and requires further workup and biopsy.

Rhabdomyolysis

If a patient's urinalysis is positive for heme but does not have the presentation of red blood cells, most likely the patient is experiencing ________ rather than a bleed.

White blood cells

If there are ______ present in the urine, this is not strong enough evidence to start treatment for an UTI unless the patient is showing common UTI symptoms, is pregnant or is undergoing a urologic evaluation.

Interstitial nephritis

If a patient's urine has white blood cells, hyaline casts and eosinophils present, this may indicate that the patient is experiencing _______ and the drug that is causing this drug-induced disease must be identified and removed.

MDRD

Which estimated creatinine clearance equation utilizes race thus has fallen out of favor with some practitioners?

A. CKD-EPI, 2021

B. Cockcroft-Gault

C. MDRD