Pathology Cheat Sheet
Interpret the Panel Pattern
Laboratory panels for NEET-PG: hepatocellular vs cholestatic LFTs, AST/ALT ratio, urea-creatinine ratio, TSH interpretation, INR, and PT vs aPTT tests.
MedNext Academy | 3 min read
Interpret the Panel Pattern
Laboratory panels for NEET-PG: hepatocellular vs cholestatic LFTs, AST/ALT ratio, urea-creatinine ratio, TSH interpretation, INR, and PT vs aPTT tests.
The interpretation of common laboratory panels including liver, renal, lipid, thyroid, and coagulation profiles.
High-yield lines
- Liver function tests separate hepatocellular injury with high transaminases from cholestatic injury with high alkaline phosphatase.
- A very high AST-to-ALT ratio suggests alcoholic liver disease.
- Conjugated hyperbilirubinaemia with high alkaline phosphatase and GGT indicates cholestasis.
- Serum albumin and prothrombin time reflect the synthetic function of the liver.
- Renal function tests use serum urea and creatinine, and estimated GFR grades chronic kidney disease.
- A raised urea-to-creatinine ratio suggests prerenal azotaemia from volume depletion.
- The lipid profile measures total cholesterol, LDL, HDL, and triglycerides for cardiovascular risk.
- Thyroid function tests interpret TSH with free T4, where high TSH and low T4 indicate primary hypothyroidism.
- Low TSH with high T4 indicates primary hyperthyroidism.
- The coagulation profile uses the prothrombin time for the extrinsic pathway and the aPTT for the intrinsic pathway.
- The INR standardises the prothrombin time to monitor warfarin therapy.
- Isolated aPTT prolongation suggests intrinsic factor deficiency such as haemophilia or a lupus anticoagulant.
Mapped competency codes
- PA23.3
Continue into the full chapter
This summary maps to PA23-clinical-pathology.
Frequently Asked Questions
How do liver function tests distinguish hepatocellular from cholestatic injury?
Hepatocellular injury raises the transaminases predominantly, while cholestatic injury raises alkaline phosphatase and GGT with conjugated hyperbilirubinaemia.
How are thyroid function tests interpreted?
By reading TSH with free T4: a high TSH with low T4 indicates primary hypothyroidism, whereas a low TSH with high T4 indicates primary hyperthyroidism.
What does a raised urea-to-creatinine ratio suggest?
Prerenal azotaemia from volume depletion, in which increased urea reabsorption raises urea disproportionately to creatinine.
Which coagulation test monitors warfarin?
The prothrombin time expressed as the INR, which standardises results to guide warfarin dosing.
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