How to read your eGFR and creatinine results, and what else can push creatinine up

Your eGFR estimates how well your kidneys filter your blood, and it's calculated from your creatinine, so a high creatinine and a low eGFR usually tell the same story. One result on its own isn't a diagnosis of kidney disease.

Creatinine is a waste product from your muscles. When kidney filtering slows, it builds up and eGFR falls. Numia's Electrolytes Panel measures it alongside urea, a second waste marker your kidneys clear.

Why know these numbers before anything feels wrong? Early kidney disease rarely causes symptoms. A JAMA review found fewer than 5% of people with early chronic kidney disease (CKD) knew they had it. That's why a baseline from Numia's panel helps: it's your number to compare with later.

What does my eGFR mean?

A first eGFR of 50–60 with no other sign of damage may not mean CKD.

What else can push creatinine up?

Before trying to lower creatinine, check whether it reflects your kidneys at all. Creatinine comes from muscle, so the KDIGO kidney guideline lists muscle mass, creatine supplements and high-protein diets as non-kidney influences. A cooked-meat meal, dehydration, hard exercise, the antibiotic trimethoprim and the cholesterol drug fenofibrate can raise it too. Never stop a prescribed medication to change a number.

That's why preparation matters. HealthLinkBC advises no strenuous exercise for 48 hours and no more than about 225 g (8 oz) of meat in the 24 hours before. Numia's morning home draw needs no fasting and can follow a rest day.

When is a result urgent?

Most results mean a talk with your doctor, not an emergency. Potassium and sodium can be different: LifeLabs BC treats potassium below 2.5 or above 6.5 mmol/L, and sodium below 120 or above 160, as critical.

• Call 9-1-1 if a potassium or sodium result is flagged and you feel unwell: a too-slow, too-fast or fluttering heartbeat, marked weakness, new confusion or a seizure.
• Flagged but feeling fine? Contact the clinician who ordered the test promptly, or call HealthLink BC at 8-1-1.
• A fast rise needs prompt care: creatinine up more than 26 µmol/L within 48 hours, or to 1.5 times baseline (BC's guideline).

Where does Numia fit?

The public route, funded when clinically indicated, runs through separate appointments and a lab visit. Numia Health keeps it in one place: a licensed Canadian physician approves your requisition (lab order) online within 24 hours, a BC-licensed clinician visits your home for a 10-minute morning draw, and plain-English results reach the Numia app in 7 days. Out-of-range results are physician-reviewed with next steps. It's an HSA-eligible service.

Frequently asked questions

How can I bring my creatinine down and check it's working?

Rule out non-kidney causes, then retest after 48 hours without hard exercise. If it stays high, your physician may focus on blood pressure, blood sugar, NSAID painkillers and smoking. Repeat results show whether it's working.

Can creatine or muscle make my creatinine look high?

Yes. Muscle, creatine and high-protein diets all raise creatinine, and a 2025 meta-analysis found creatine did so without changing filtration. Your physician decides whether to pause it before a retest.

Cystatin C vs creatinine for athletes: can I get it in BC?

Cystatin C is a filtration marker less affected by muscle, but BC's 2025 guideline says it's "not currently available in BC." Instead, pair a rested creatinine retest on Numia's panel with a urine test from your doctor.