Basic terms and abbreviations
The following standardized abbreviations are regularly used in clinical practice and medical documentation related to nephrology and concomitant cardiac pathology:
- CKD — chronic kidney disease.
- eGFR — estimated glomerular filtration rate. This is a key calculated parameter reflecting the volume of plasma cleared by the kidneys per minute.
- PCI — percutaneous coronary intervention. Frequently mentioned in the context of comorbid patients with cardiorenal syndrome.
- NSTE-ACS — non-ST-segment elevation acute coronary syndrome. Another related cardiac condition requiring special attention in concomitant renal impairment.
CKD classification by GFR level
The basis for determining the stage of chronic kidney disease is the glomerular filtration rate (GFR) measured in mL/min/1.73 m². Each stage corresponds to a specific code in the International Classification of Diseases, 10th Revision (ICD-10).
| CKD stage | GFR level | ICD-10 code | Official name |
|---|---|---|---|
| G1 | >90 | N18.1 | Chronic kidney disease, stage 1 |
| G2 | 60–89 | N18.2 | Chronic kidney disease, stage 2 |
| G3a | 45–59 | N18.3 | Chronic kidney disease, stage 3 |
| G3b | 30–44 | see note | Chronic kidney disease, stage 3 |
| G4 | 15–29 | N18.4 | Chronic kidney disease, stage 4 |
| G5 | <15 | N18.5 | Chronic kidney disease, stage 5 |
Important coding nuances: If the patient's disease stage is not established or specified at the time of examination, the special code N18.9 (Chronic kidney disease, unspecified) is used in medical documentation.
Peculiarities of prescribing hypoglycemic drugs
Chronic kidney disease imposes severe limitations on the pharmacotherapy of concomitant diseases. Specifically, there is a strict rule when treating diabetes mellitus in patients with nephrological pathology:
When prescribing any hypoglycemic drugs, the attending physician must first take into account the current level of the glomerular filtration rate (GFR). The feasibility of using a specific medicinal product and its safe dosage, which avoids toxic effects on the kidneys, directly depend on this parameter.
To memorize ICD-10 codes for CKD, note the direct relationship: the digit after the decimal point in the code (N18.X) strictly corresponds to the stage number (from 1 to 5). The exception is stage 3, which is subdivided into "a" and "b".
Class and exam questions
Which parameter is decisive for staging chronic kidney disease?
The main criterion for distinguishing CKD stages is the glomerular filtration rate (GFR), measured in mL/min/1.73 m².
How to properly code an ICD-10 patient if the CKD stage is unknown?
For cases of chronic kidney disease with an unspecified stage, code N18.9 is applied.
What is the main condition to follow when prescribing diabetes therapy to a patient with CKD?
When choosing and prescribing hypoglycemic drugs, it is critically important to consider the estimated glomerular filtration rate (eGFR).
Which GFR level corresponds to the end-stage (fifth stage) of CKD?
Stage G5 is established when the glomerular filtration rate drops below 15 mL/min/1.73 m² (ICD-10 code — N18.5).
What else to study on this topic
- Formulas and methods for determining the estimated glomerular filtration rate (eGFR)
- Clinical differences and management tactics for patients at stages G3a and G3b
- Specifics of performing percutaneous coronary intervention (PCI) in patients with renal failure
- Pharmacokinetic specifics of hypoglycemic drugs depending on the CKD stage
- Management of patients with non-ST-segment elevation acute coronary syndrome (NSTE-ACS) against the background of severe CKD
Master the entire topic in the "Propaedeutics" course
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Prepared by WhiteCoat Pro faculty in accordance with the medical school curriculum. For educational purposes only.