Serum creatinine mg/dL to µmol/L Converter

Creatinine in two units: the short answer

To convert serum creatinine from mg/dL to µmol/L, multiply by 88.4. To convert µmol/L back to mg/dL, divide by 88.4. A creatinine of 1.0 mg/dL is therefore 88 µmol/L, and 120 µmol/L is 1.36 mg/dL. The converter above handles both directions and compares the result with typical adult ranges for men and women.

Creatinine is the most widely used blood test of kidney function, and its unit matters in a way it does not for many other tests: creatinine is fed into equations such as eGFR and creatinine clearance, and putting the wrong unit into an equation produces a wildly wrong answer. This guide explains the conversion, what creatinine reflects, typical ranges by sex and age, how creatinine relates to eGFR, and the factors that move it independently of the kidneys.

What creatinine is and why it is measured

Creatinine is a waste product formed at a fairly steady rate from creatine in muscle. It is filtered out of the blood by the kidneys' glomeruli and excreted in urine, with a small additional amount actively secreted by the kidney tubules. Because production is roughly constant from day to day, the blood level mainly reflects how well the kidneys are filtering: when filtration falls, creatinine rises.

Creatinine is included in routine metabolic panels (often called U&E or renal profile outside the US). It is used to:

• screen for and monitor chronic kidney disease (CKD), particularly in people with diabetes or high blood pressure
• detect acute kidney injury (AKI) in hospital
• adjust the doses of medicines that are cleared by the kidneys
• check kidney function before imaging with contrast or before certain medicines
• estimate glomerular filtration rate (eGFR)

mg/dL and µmol/L explained

mg/dL (milligrams per deciliter) is used in the United States and some other countries.

µmol/L (micromoles per liter), sometimes written umol/L or mcmol/L, is the SI unit used in the UK, Europe, Canada, Australia and most other countries.

Because the numbers differ by a factor of almost 90, they rarely get confused with each other, but they can be confused in equations. A creatinine of "1.1" is obviously mg/dL; a creatinine of "97" is obviously µmol/L.

Why the factor is 88.4

Creatinine's molar mass is 113.12 g/mol. One micromole weighs 113.12 µg. A concentration of 1 mg/dL is 10 mg per liter, or 10,000 µg per liter, which is 10,000 ÷ 113.12 = 88.4 µmol/L. Some sources use 88.42, others 88; the differences are trivial.

How to convert creatinine step by step

1. Check the unit on the report.
2. For mg/dL to µmol/L, multiply by 88.4 and round to a whole number.
3. For µmol/L to mg/dL, divide by 88.4 and round to two decimal places.

Worked examples

• 0.6 mg/dL × 88.4 = 53 µmol/L
• 0.9 mg/dL × 88.4 = 80 µmol/L
• 1.2 mg/dL × 88.4 = 106 µmol/L
• 1.5 mg/dL × 88.4 = 133 µmol/L
• 2.0 mg/dL × 88.4 = 177 µmol/L
• 70 µmol/L ÷ 88.4 = 0.79 mg/dL
• 150 µmol/L ÷ 88.4 = 1.70 mg/dL
• 354 µmol/L ÷ 88.4 = 4.00 mg/dL – a value used as a threshold in acute kidney injury staging.

Mental shortcut

Multiply mg/dL by 90 and subtract a little, or divide µmol/L by 90 and add a little. For 1.3 mg/dL: 1.3 × 90 = 117, the exact answer is 115.

Creatinine conversion chart

Normal creatinine ranges

Typical adult reference ranges are about 0.74–1.35 mg/dL (65–119 µmol/L) for men and 0.59–1.04 mg/dL (52–92 µmol/L) for women. Men usually have higher values because they have more muscle mass on average. Laboratory ranges vary a little by method.

Children

Children have much lower creatinine because they have less muscle. A healthy toddler may have a creatinine of about 0.2–0.4 mg/dL (18–35 µmol/L), and values rise gradually through childhood and adolescence. A "normal adult" value of 1.0 mg/dL would be abnormal in a young child. Newborns initially reflect the mother's creatinine for the first days of life. Paediatric results must be compared with age-specific ranges, and children's eGFR is estimated with separate equations.

Older adults

Older adults often lose muscle, so their creatinine may stay "normal" even when kidney function has declined. This is a key reason clinicians rely on eGFR rather than creatinine alone, and why eGFR equations include age.

Pregnancy

Kidney filtration rises by up to 50% in pregnancy, so creatinine falls. A creatinine of about 0.9 mg/dL (80 µmol/L) or higher may already be abnormal in pregnancy, even though it is within the non-pregnant range.

Why creatinine is not the whole story: eGFR

The relationship between creatinine and kidney function is not linear. Early in kidney disease, filtration can fall by half while creatinine only rises from, say, 0.8 to 1.2 mg/dL (71 to 106 µmol/L) – a change that can stay within the "normal" range. Later, small further falls in filtration cause much larger rises in creatinine.

To address this, laboratories report an estimated glomerular filtration rate (eGFR), calculated from creatinine, age and sex. In the US, the recommended equation since 2021 is the race-free CKD-EPI 2021 equation. In the UK and Europe, CKD-EPI (often the 2009 version) is also standard. The equations are written for creatinine in mg/dL; laboratories reporting in µmol/L divide by 88.4 inside the calculation.

Examples using CKD-EPI 2021 show how much the same creatinine can mean:

• A 30-year-old woman with creatinine 1.0 mg/dL (88 µmol/L) has an eGFR of about 78.
• A 70-year-old man with the same creatinine has an eGFR of about 81.
• A 75-year-old woman with creatinine 1.2 mg/dL (106 µmol/L) has an eGFR of about 47 – stage 3a CKD if persistent.

Our eGFR calculator accepts creatinine in either unit and does the conversion for you.

Cystatin C

When creatinine may be misleading – very high or low muscle mass, amputations, vegetarian diets, or when eGFR is near a treatment threshold – guidelines such as KDIGO recommend measuring cystatin C and using a combined creatinine–cystatin C equation. Cystatin C is less affected by muscle mass.

Creatinine in acute kidney injury

In hospital, a rapid rise in creatinine is used to diagnose acute kidney injury. Under the KDIGO criteria, AKI is defined as:

• a rise of 0.3 mg/dL (26.5 µmol/L) or more within 48 hours, or
• a rise to 1.5 times baseline or more within the previous seven days, or
• urine output below 0.5 mL/kg/hour for six hours.

Stage 3 AKI includes a creatinine of 4.0 mg/dL (354 µmol/L) or more, three times baseline, or the need for dialysis. Note that the absolute thresholds are given in both units in the guideline, and converting correctly matters when a patient's results come from different laboratories.

CKD stages and what they mean in creatinine terms

Chronic kidney disease is staged by eGFR (G1 to G5) and by urine albumin (A1 to A3), not by creatinine directly. Still, it can help to see roughly what creatinine values correspond to each stage for a typical person. The table below was calculated with the CKD-EPI 2021 equation for a 60-year-old and would differ for other ages.

A diagnosis of CKD requires the abnormality to persist for more than three months. A single raised result, particularly during an illness, is not enough.

Tracking creatinine over time

The most useful creatinine result is often your own previous one. A rise from 0.7 to 1.0 mg/dL (62 to 88 µmol/L) can be within the "normal" range yet represent a loss of around a third of filtering capacity. When comparing results from different countries, convert them to one unit first, and note whether the same type of assay was used.

Some medicines cause an expected small rise in creatinine when started. ACE inhibitors, angiotensin receptor blockers and SGLT2 inhibitors often raise creatinine by up to about 30% in the first weeks by reducing pressure inside the glomeruli. This "dip" in eGFR is usually not a sign of harm, and in the long term these medicines protect the kidneys. A rise larger than about 30%, however, should be reviewed.

What affects creatinine results

• Muscle mass – bodybuilders and very muscular people may have high creatinine with healthy kidneys; frail people, amputees and people with muscle-wasting conditions may have low creatinine with poor kidney function.
• Diet – a large meal of cooked meat can raise creatinine by up to about 0.2–0.3 mg/dL (18–26 µmol/L) for several hours. Avoiding cooked meat for 12 hours before the test is advised in some guidance, including the UK's NICE.
• Creatine supplements – raise creatinine somewhat without harming the kidneys.
• Strenuous exercise shortly before the test.
• Medicines that block tubular secretion – trimethoprim, cimetidine, dolutegravir, cobicistat and some others raise creatinine by around 0.1–0.3 mg/dL without changing true filtration.
• Dehydration reduces kidney blood flow and raises creatinine, often reversibly.
• Laboratory method – older Jaffe methods can be affected by ketones, very high bilirubin and some drugs; enzymatic methods are more specific. Modern assays are traceable to an isotope-dilution mass spectrometry (IDMS) reference.

Creatinine and medicine dosing

Many medicines are removed from the body by the kidneys, and their doses are adjusted when kidney function is reduced. Common examples include metformin, some antibiotics, anticoagulants such as apixaban and rivaroxaban, gabapentin, digoxin and lithium. Drug labels and dosing guides use one of three measures:

• eGFR in mL/min/1.73 m², which most laboratories report automatically.
• Creatinine clearance estimated with the Cockcroft-Gault equation, which uses creatinine, age, weight and sex and is reported in mL/min. Many older drug labels were developed with this method.
• Serum creatinine thresholds, used occasionally, for example in some anticoagulant dose rules.

When a dosing rule gives a creatinine threshold in mg/dL and your result is in µmol/L, convert first. For instance, a threshold of 1.5 mg/dL corresponds to 133 µmol/L. Our creatinine clearance calculator accepts either unit for this reason.

Urine creatinine and the albumin-to-creatinine ratio

Creatinine is also measured in urine, where it serves as a reference for other urine tests. Because urine concentration varies with how much a person drinks, dividing urine albumin by urine creatinine gives a ratio – the urine albumin-to-creatinine ratio (UACR) – that is far more reliable than albumin alone. Urine creatinine is usually reported in mg/dL in the US and in mmol/L elsewhere (1 mmol/L = 11.3 mg/dL). The UACR is reported in mg/g or mg/mmol; a value of 30 mg/g, the threshold for moderately increased albuminuria, corresponds to about 3 mg/mmol. Our UACR converter handles that conversion.

When to see a doctor

See a doctor if your creatinine is above your laboratory's range, if your eGFR is below 60 on two tests at least three months apart, or if creatinine has risen noticeably compared with your previous results even if still "normal". Seek urgent care if a rise is accompanied by greatly reduced urine output, swelling, breathlessness, confusion or severe vomiting. People with diabetes, high blood pressure, heart disease or a family history of kidney disease should have kidney function checked regularly, including a urine albumin-to-creatinine ratio.