MTAP1 - CC NPN, BG1&2, Liver Function

Which non-protein nitrogen (NPN) compound is found in the highest concentration in both human plasma and urine, and which is the least abundant in plasma?

Urea (Highest); Ammonia (Least)

Amino acids are present in human plasma but entirely absent from normal urine. Which enzyme is responsible for the complete renal tubular reabsorption of amino acids?

Gamma-glutamyl transferase (GGT)

A patient's laboratory results show a Urea value of 90 mg/dL. What is this patient's estimated Blood Urea Nitrogen (BUN) concentration in mg/dL?

42.05 mg/dL

A high BUN:Creatinine ratio >20:1 accompanied by an elevated plasma Creatinine level and an obstruction of the renal collecting system is characteristic of which category of azotemia?

Post-Renal Azotemia

In the commonly used kinetic GLDH coupled enzymatic reaction for BUN measurement, what specific molecular disappearance is measured spectrophotometrically at 340 nm?

Disappearance/Oxidation of NADH

When collecting a plasma sample for blood urea nitrogen analysis, which anticoagulants must be strictly avoided because they inhibit the primary action of the enzyme urease?

Sodium Citrate and Sodium Fluoride

In the non-enzymatic Caraway chemical method for uric acid determination, phosphotungstic acid is reduced by uric acid in an alkaline solution to form which measured product?

Tungsten blue

An inherited deficiency of the purine salvage enzyme hypoxanthine-guanine phosphoribosyltransferase (HGPRT) is seen exclusively in males and results in severe hyperuricemia. What is this condition called?

Lesch-Nyhan Syndrome

Which muscular biomarker is completely independent of dietary protein intake, is inversely proportional to the Glomerular Filtration Rate (GFR), and forms a red-orange chromogen when reacted with alkaline picrate?

Creatinine

An acute, fatal metabolic failure of the liver characterized by severe fatty infiltration of the liver parenchyma and neurotoxic encephalopathy following a childhood viral infection (e.g., varicella or influenza) is known as:

Reye's Syndrome

When a patient experiences a shift to the right in their oxygen dissociation curve due to acidosis, how is the affinity of hemoglobin for oxygen modified?

The affinity is decreased, meaning hemoglobin releases oxygen more easily.

What are the specific reference electrodes and sensor membranes built into an automated blood gas analyzer to directly measure arterial blood pH and pCO2, respectively?

Microglass Electrode (pH) and Severinghaus Electrode pCO2

In an automated colorimetric method for total CO2 content, gaseous CO2 is dialyzed through a silicone-rubber membrane into a solution containing cresol red at pH 9.2. How is total CO2 quantitated?

By measuring a decrease in color intensity at 430 nm caused by a falling pH

If an arterial blood gas (ABG) sample is drawn into a plastic syringe and left uncapped at room temperature for an extended period before analysis, how will the results be affected?

pH increases, pO2 increases, pCO2 decreases

An enzyme panel pattern demonstrating a slight increase in ALT and AST alongside a marked increase in Alkaline Phosphatase (ALP) and Gamma-glutamyl transferase (GGT) is most highly consistent with:

Obstructive Jaundice / Hepatobiliary Damage

Which inherited hyperbilirubinemia syndrome is caused by a complete autosomal recessive absence of the conjugating enzyme UDP-glucuronyltransferase (UDPGT), resulting in severe kernicterus and early death?

Crigler-Najjar Syndrome (Type 1)

What are the key analytical differences between the Evelyn-Malloy and Jendrassik-Grof manual methods for serum total bilirubin measurement?

Evelyn-Malloy uses 50% methanol to yield a red-purple color at 560 nm; Jendrassik-Grof uses caffeine-sodium benzoate to yield a blue color at 600 nm.