Past Papers · SAQ
Liver Function Tests
2024A Q15
Exam questionOutline how the measurement of the following can be used in the assessment of liver function (25% of marks each): (i) Albumin (ii) Prothrombin time (PT) (iii) Glucose (iv) Ammonia.
CICMWrecks answer
Master answer
Table of LFT values and clinical significance
(LIMITED)
| Test | Reference Range | Clinical Significance |
|---|---|---|
| Serum proteins (including albumin, globulin, fibrinogen) | Total protein 60-80 g/L Albumin 35-45 g/L Globulin 25-35 g/L Fibrinogen 2-4 g/L | Liver synthesises nearly all plasma proteins (except Ig’s) |
| ↓ serum total protein, albumin, globulin and fibrinogen levels suggest impaired synthetic function due to hepatocellular damage | ||
| Non-specific → also can suggest nephrotic syndrome, malnutrition states, burns, Etc. | ||
| Note – Albumin is a long-term marker of liver function (as t ½ 20 days) → ↓ albumin means chronic liver dysfunction (as it can be normal with acute liver disease) | ||
| Coagulation studies (INR and PT) | INR >1.2 PT 10-15 s | Hepatocytes synthesise clotting factors (incl vitamin K-dependent CFs) |
| ↑ PT or INR suggests either (i) impaired CF synthesis (hepatocellular damage → acute liver dysfunction), or (ii) vitamin K malabsorption (cholestasis) | ||
| Non-specific → also can suggest warfarin use, DIC, Etc. | ||
| Plasma glucose | BGL 4-8 mmol/L | Liver has vital role in glucostat function (glycolysis, glycogen metabolism, gluconeogenesis) |
| BGL derangements suggest hepatocellular dysfunction | ||
| Non-specific → also can suggest DM, insulin use, Etc. | ||
| Plasma ammonia/urea | NH3 < 35 umol/L Urea 3-7 umol/L | Liver converts toxic NH3 (metabolite of a.a. and pyrimidine) into less toxic urea for renal excretion via the “urea cycle” |
| ↑ NH3 and ↓ urea suggests hepatocellular damage |
Bianca 2020
Past papers
Exam appearances
| Exam | Exact exam wording | Candidate success |
|---|---|---|
| 2024A Q15 | Outline how the measurement of the following can be used in the assessment of liver function (25% of marks each): (i) Albumin (ii) Prothrombin time (PT) (iii) Glucose (iv) Ammonia. | 56% |
| 2021B Q07 | Outline how the measurement of the following can be used in the assessment of liver function (25% marks of each): • Albumin • Prothrombin time • Glucose • Ammonia | 54% |