Yes, certain investigations do need fasting status.
The most common investigations which require fasting include :-
Lipid Profile – 12 Hours
Blood Sugar Fasting – 10 to 12 Hours
Insulin Fasting – 10 to 12 Hours
C Peptide Fasting – 8 to 10 Hours
Ultrasound – Whole abdomen, Upper abdomen
Common investigations which do not require fasting include :-
Kidney Function Test (Urea, Creatinine, Uric Acid, Electrolytes)
Liver Function Test (Bilirubin Total, Direct, SGOT, SGPT, Alkaline Phosphatase, GGTP)
Thyroid Function Test
It is always advisable to talk to the lab In-charge and clarify in advance.