Advance from patient depends on hospital terms & conditions. Payment is done by patient (non business person ), if the amount is refundable then no need to book income at the time of receipts but income can be booked by the hospital at the time of raising invoice. 
The advance from patient may be shown in advance account ledger untill invoice raised by hospital for booking of income. 
But advance received is subject to GST as per rule 50 of GST act.

CGST Rule 50: Receipt Voucher (Chapter-VI: Tax Invoice, Credit and Debit Notes)

A receipt voucher referred to in clause (d) of sub-section (3) of section 31 shall contain the following particulars, namely,-
(a) name, address and Goods and Services Tax Identification Number of the supplier;
(b) a consecutive serial number not exceeding sixteen characters, in one or multiple series, containing alphabets or numerals or special characters -hyphen or dash and slash symbolised as “-” and “/” respectively, and any combination thereof, unique for a financial year;
(c) date of its issue;
(d) name, address and Goods and Services Tax Identification Number or Unique Identity Number, if registered, of the recipient;
(e) description of goods or services;
(f) amount of advance taken;
(g) rate of tax (central tax, State tax, integrated tax, Union territory tax or cess);
(h) amount of tax charged in respect of taxable goods or services (central tax, State tax, integrated tax, Union territory tax or cess);
(i) place of supply along with the name of State and its code, in case of a supply in the course of inter-State trade or commerce;
(j) whether the tax is payable on reverse charge basis; and
(k) signature or digital signature of the supplier or his authorised representative:
Provided that where at the time of receipt of advance,-
(i) the rate of tax is not determinable, the tax shall be paid at the rate of eighteen per cent.;
(ii) the nature of supply is not determinable, the same shall be treated as inter-State supply.