There are few ways you can use to Upgrade the certificate issue by polytechnic in Nigeria to BSC.
The method will be discuss briefly below.
National Diploma: upgrading your national diploma result is not too difficult in the present condition of Nigeria Educational. System.
You can Apply For Direct entry into 200 level.
Although most school demand for upper credit as criteria for direct entry Admission.

HND : you may upgrade your ND result to HND and after your HND you can gain Admission to 300 level in any Nigeria university if you graduated with upper credit while candidates that graduated with lower credit will be consider into 200 level.

HND conversion: Another platform you can use to convert your HND to BSC is by obtaining HND conversion programme in some Nigeria universities.
Conversion programme always take up to 3 or 4 Academic session.

Take ICAN : holders of Ican ATS 3 certificate can also apply for direct entry into 200 level.
Candidate with national diploma with a lower grade or pass can enrol for ICAN ATS exam.

PGD : lastly all Hnd certificate holder can run a post graduate diploma programme to upgrade their certificate in the labour market.

Source
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