Liver:- Part 2 – Liver function tests and Jaundice Classification

August 11, 2026Chemical pathology Lab Tests

Table of Contents

Liver Function Tests

What sample is needed for Liver Function Tests?

Venous blood is needed to prepare the serum.

What tests are recommended to evaluate liver function?

Total Bilirubin.
1. Direct bilirubin.
2. Indirect bilirubin.
SGPT.
SGOT.
Alkaline phosphatase.
Gamma-glutamyltransferase (γ-GT).
Total protein.
Albumin
A / G ratio.
Prothrombin time (PT).
Ultrasound of the abdomen to evaluate the liver or any other mass in the abdomen.
Viral markers.

What are the normal values of liver function tests?

Test	Normal value
Total bilirubin	o.3 to 1.0 mg/dL
Conjugated bilirubin	0.1 to 0.3 mg/dL
Unconjugated bilirubin	0.1 to 0.8 mg/dL
Newborn total bilirubin	1.0 to 12.0 mg/dL.
Alkaline phosphatase	Adult = 30 to 120 units/L Child <2 years = 85 to 235 units/L 2 to 8 years = 65 to 210 units/L 9 to 15 years = 60 to 300 units/L 16 to 21 years = 30 to 200 units/L
SGOT (AST)	Adult = 0 to 35 units Elderly = values slightly higher than adults Newborn and infants = 15 to 60 units/L
SGPT (ALT)	Adult and child = 4 to 40 units/L Infants may be twice as high as the adult value
Albumin	Adult = 3.5 to 5 g/dL Premature infants = 3 to 4.2 g/dL Newborn = 3.5 to 5.5 g/dL Infant = 4.4 to 5.4 g/dL Child = 4 to 5.9 g/dL
Total protein	6.4 to 8.3 g/dL
A/G ratio	0.8 to 2.0
Gamma-glutamyltransferase (γ-GT).	>45 years = 8 to 38 units/L Female <45 years = 5 to 27 units/L Childlike adult level Newborn = 5 times higher than the adult level
Prothrombin time (PT)	11 to 12.5 seconds Anticoagulant therapy = 1.5 to 2 times control
Ultrasound	No organomegaly
Viral markers	Negative

Liver function tests and differential diagnosis

What are the phases of jaundice?

Preicteric phase.
Icteric phase.
Nonicteric phase.

Preicteric phase:

In this phase, urine and bilirubin are usually positive 1 to 6 days before the onset of clinical jaundice.
Urinary urobilinogen is usually increased.
The BSP test is usually the first test to become positive in this phase.
Thymol flocculation, turbidity tests, and cephalin flocculation tests are positive in the late phase of jaundice.

Icteric phase:

Direct bilirubin is increased.
Urinary urobilinogen is increased, and bile is present in the urine.
Alkaline phosphatase may or may not be elevated.
The thymol turbidity and flocculation tests and the cephalin flocculation test were positive.
The Bromsulphalein test is not helpful.

Non-icteric phase:

Urinary urobilinogen is increased.
Thymol-flocculation and turbidity and cephalin flocculation tests are usually positive.
The Albumin-globulin ratio shows high globulin and low serum albumin.
Alkaline phosphatase and cholesterol ester may or may not be helpful.

Jaundice phases

How will you classify jaundice?

The major causes of jaundice are:

Pre-hepatic jaundice where there is hemolysis.
Hepatic jaundice is where intrahepatic biliary tract obstruction occurs.
Post-hepatic jaundice is when extrahepatic biliary tract obstruction occurs.

jaundice classification

Please see more details in the LFT part.

Questions and answers:

Question 1: What is the value of GGT?

Question 2: Which bilirubin will be raised in obstructive jaundice?

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Comments

MUMTAZ AHMED Reply

October 6, 2022

I am very thankful to you for sharing this type of informatic site for us thank you so much sir

Dr. Riaz Reply

Thanks.

Dr SK Khilar Reply

June 25, 2024

An asymptomatic 24 yr male, no comorbidities on LFT has mildly raised serum bilorubin as well as mildly raised direct bilirubin, with rest all enzymes normal. HOW DO I INTERPRET THIS OR WHAT FURTHER INVESTIGATIONS DO I ASK HIM TO DO?

This is one of the congenital jaundices. Please see this topic and this may solve your problem.
https://labpedia.net/gilberts-syndrome-signs-symptoms-and-diagnosis/