Chapter 12 Clin Chem

An urea N result of 9 mg/dl is obtained by a technologist. What is the urea concentration

19.3 mg/dl

Azotemia refers to

An increase in urea in blood

True or false? Indirect urea methods begin with the hydrolysis of urea to ammonia

True

True or false? Serum uric acid levels may be elevated in patients undergoing cancer chemotherapy.

True

which one of the listed conditions is not associated with elevated plasma uric acid concentration?

allopurinol overtreatment

Consider the following lab results. what is the most likely cause of this patient's BUN? BUN 45 mg/dL Creatinine 1.8 mg/dL Uric Acid 7 mg/dL pH 7.22 pCO2 74.4 mm Hg pO2 32.8 mm Hg O2 sat. 51.3% What is the most likely cause of this patient's BUN?

Congestive heart failure

Which of the following best describes the correct collection and handling conditions for a blood ammonia measurement

Draw sodium heparin tube, place in ice bath immediately, separate cells and plasma in refrigerated centrifuge, immediately remove plasma and freeze if analytical testing is delayed

True or false? Serum urea levels are less affected by diet and metabolism than are serum creatinine levels

False

The major causes of decreased plasma urea concentration include

Low protein intake and sever liver disease

Monitoring of _______ in patients on chemotherapy due to leukemia, lymphoma or multiple myeloma is necessary to avoid nephrotoxicity

Serum uric acid

A toxic condition involving a very high serum level of urea and creatinine accompanied by failure of the three main functions of the renal system is referred to as

Uremia

the abbreviated Modification of Diet in Renal Disease (MDRD) equation considers all of the following variables EXCEPT

Urine creatinine concentration

Which one of the following is not an NPN substance?

allantoin

Uric acid is the product of

allantoin metabolism

Prerenal azotemia is caused by

congestive heart failure

A MLT obtains a urea N value of 61 mg/dl and a serum creatinine value of 2.5 mg/dl on a patient. These results indicate

glomerular nephritis

Ammonia concentrations are usually measured to evaluate

hepatic encephalopathy

Urea:

Is synthesized from CO2 and ammonia

Which compound constitutes nearly half of the NPN substances in the blood?

urea