There are different parameters considered in Ayurvedic prognosis, to decide a particular disease in a specific stage in a specific patient is curable, easily curable, not curable, just maintainable etc. Before committing to treat the patient, the doctor has to make this critical decision. There are 42 and more criteria explained for this purpose in 10th chapter of Sutrasthana of Charaka Samhita.
The 10th chapter is called as Maha Chatushpada Adhyaya.
Chatushpada means the 4 basic elements of treatment that were covered in the last chapter. This chapter further elaborates on the subject of the last chapter.
Shloka recitation video
Role of therapeutics in treatment
What is the role of therapeutics in treating diseases?
Sage Maitreya puts a query –
Some patients get cured easily from diseases, when they are treated with proper medicines, attendants, and well qualified physicians, who also have self-control. On the other hand in spite of all these some die. What is the cause? So therapeutics is of no value in the eradication of diseases. This is just like a drop of water thrown into a ditch or pond or a handful of dust thrown in a flowing river or on a heap of dust. To sum up: with the same therapeutic measures, some patients get healed and some die. Similarly, when no therapeutic measures are undertaken, then also some patients recover and some die. So, what is the significance of treatment at all? When the outcomes are totally unpredictable? 
Answer by Sage Atreya –
Oh, Maitreya! the conclusion derived by you is incorrect. Because, to say that the patients adopting the therapeutic measures having the sixteen qualities die is far from fact; Therapeutic measures can never be ineffective in curable diseases. Similarly even in such cases where patients are cured without proper medicines, etc. it should be understood that, had there been proper administration of therapeutic measures the process of cure would have been quicker and better; this can be likened to the lifting of a person who has fallen; he can no doubt get up himself but if he is helped and lifted by another person, he would get up sooner without much difficulty. Such is the case with patients who get cured without any treatment.
Regarding cases where patients die even by taking adequate treatment, it is not that all patients taking sufficient treatment are necessarily cured because all diseases are not curable. The diseases that are curable can only be cured by proper treatment. Those which are not curable will certainly do not respond to treatment. Not even the ablest physician is capable of curing a patient with an incurable disease.
Able physicians always proceed with their treatment after proper examination. As an archer having the knowledge and practice of archery shoots arrows with the help of his bow and does not commit mistakes in hitting the target, a physician endowed with his own qualities and other accessories proceeding with the treatment after proper examination, will certainly cure a curable patient without fail. So application of therapeutic measures has its own special significance. 
Examples to prove role of therapeutics
Examples of therapeutic principles, to prove the role of therapeutics:
And we see with our eyes that we cure a weak patient by providing nourishment, obese and over-nourished patients with Apatarpana (depletion therapy, cleansing), a patient with cold affliction with hot remedies, a patient with hot affliction with cold remedies, an emaciated patient with nourishment, etc. We treat the patient with principles that are opposite to the qualities of the disease. By this, we restore the natural balance (Prakruti) of the patient. Thus the group of therapeutic measures are the best tools in managing diseases. 
Importance of correct prognosis
Why right prognosis is very important in treatment?
(‘Prognosis’ means judging if a disease is treatable or not or how easy/ difficult it is to treat a disease)
A physician who can distinguish between curable and incurable diseases and initiates treatments in time with the full knowledge of therapeutics can certainly accomplish his objective of curing the disease.
On the other hand, a physician who undertakes the treatment of an incurable disease would undoubtedly subjects himself to
Arthahaani – loss of wealth
Vidyahaani – loss of knowledge
Yashohaani – loss of fame and he will also earn bad reputations, sanctions or punishments.[7-8]
Classification of diseases according to prognosis
Sadhya Vyadhi – Curable diseases are of two types-
Sukha Sadhya Vyadhi – easily curable diseases
Krichra Sadhya Vyadhi – difficult-to-cure disease
Similarly Asadhya Vyadhi – incurable diseases are two types, viz
Yapya – maintainable, the symptoms of which can be kept under check till death
Anupakrama / Pratyakhyeya / Asadhya – impossible to treat. [9-10]
Sadhya Vyadhi – easy-to cure diseases can also be classified as –
easy to cure,
moderately easy to cure and
curable with difficulty.
Sukha Sadhya Vyadhi
Features of Sukha Sadhya Vyadhi – easily treatable diseases:
- Alpa Hetu – mild / fewer causative factors
- Alpa Purvaroopa – very few premonitory symptoms are manifested
- Alpa Roopa – very few symptoms of the disease are manifested
- Na Cha Tulyaguno Dushyo – If the disease causing Dosha and the Dhatu(body tissue) are not similar; for example, Vata usually causes diseases in Asthi (bones). But if it causes disease in Meda (fatty tissue), which is the site of Kapha, such a Vata disorder is easy to treat.
- Na Doshaha Prakrutirbhavet – If the body type of the person does not match with the disease causing Dosha. For example, if Vata body type person gets Kapha dominant disease, it is easy to treat.
- Na Cha Kala Guna: Tulyo – if the season and the qualities of disease do not match; Eg: if cough and cold happens in summer, then it is easy to treat
- Ne Desho Durupakramaha – if the place of the patient is ideal, and if the site of disease manifestation is harmless,
- Gati: Eka – if the disease occurs in a single path / direction
- Navatvam – disease of recent onset
- Upadrava Na Cha – disease with no complications.
- Doshashcha ekaha – if the disease is caused by a single Dosha,
- Dehaha Sarva Aushadha Kshamaha – patient’s body is capable of tolerating all types of treatments and medicines
- Chatushpaada Upapattishcha – availability of good doctor, nurse and medicines
Krichra Sadhya Vyadhi
Features of difficult-to-cure disease: Krichra Sadhya Vyadhi –
- Madhyama Bala Nimitta – moderate causative factors
- Madhyama Purvaroopa – moderate number and strength of premonitory symptoms
- MadhyamaRoopa – moderate number and strength of characteristic features of disease
- Kala Prakruti Dushyanaam Saamanya Anyatama – Any one among seasons / body type / body tissue involved is similar to the disease causing Dosha.
- Garbhini Vruddha Baalaanaam – disease afflicting pregnant / elderly / children
- Na Ati Upadrava – not excess complications
- Shastra Kshara Agnikrutyaanaam – if the treatment involves use of Shastra – Surgery, Ksharakarma (as in piles and fistula) and Agnikarma (fire / heat treatment / cautery).
- Anavam – if the disease is not new (neither too old)
- Kruchra Deshajam – if the patient belongs to a difficult place or if the disease involves a complicated body part
- Ekapatham rogam, Naati Poorna Chatushtayam- disease afflicting a single body channel / single system but if the doctor, nurse / proper medicines are not fully available / not of good quality
- Dvipatham, Naati Kaalam – involves two body channels but disease is not very old
- Dvidoshajam – two Doshas are involved in the disease [14-16]
Features of maintainable diseases – Yapya Vyadhi Lakshana –
- Pathya Sevaya Alpa Sukham -The patient can survive by following Pathya – wholesome regimen and enjoys a little relief.
- Alpena Hetuna Ashu Pravartakam – disease gets quickly exacerbated with simple and mild causative factors
- Gambheeram – disease afflicting deep seated body tissues
- Bahu Dhatustham – disease involves many body tissues
- Marma Sandhi Samashritam – disease involves Marma (vital points of body, such as heart, groin), bones and joints (joining part of different body tissues and organs)
- Nitya Anushayi – Symptoms manifest everyday
- Deerghakaalam – chronic disease, long standing disorders
- Dvidoshajam – involves 2 Doshas. [17-18]
Anupakrama / Asadhya Vyadhis
Features of incurable diseases – prathyakhyeya / Anupakrama / Asadhya Vyadhis –
- Tridoshajam – involves all the three Doshas – Vata, Pitta and Kapha
- Kriyaapatham Atikraantam – the disease has grown beyond the abilities of all possible treatment modalities
- Sarva Marganusarinam – disease involves all the body channels / multiple systems
- Autsukya – sudden excitement in patient
- Arati – restlessness
- Sammoha – unconsciousness
- Indriyanasha – loss of functions of sense organs
- Durbalasya Susamvruddham – in a weak patient, the disease is well manifested
- Sa Arishtam – having bad prognostic signs
Importance of patient examination
A wise physician should examine the distinctive features of the diseases beforehand and then only he should start his treatment for only those diseases that are curable.
So a physician who can distinguish between curable and incurable diseases, he with his right applications will not subscribe to the wrong notions like sage Maitreya. [21-22]
Therapies, qualities of each of the four aspects of therapeutics their effects, views(in this connections) of Atreya and Maitreya, two different views, conclusion, features of all types of curable and incurable diseases – all these are described in this chapter. .[23-24]
Thus end the tenth chapter – Maha Chatushpada Adhyaya of Sutrasthana section of Agnivesha’s Charaka Samhita, as redacted by Charaka.