In short
- On a Slovenian lab report, S- in front of a test name means the test was done on serum. S-ALT is ALT measured in serum.
- Other prefixes on Slovenian lab lists: P- plasma, K- whole blood, U- urine, dU- 24-hour urine.
- Blood chemistry tests (a comprehensive metabolic panel, CMP, in the US) check the liver, kidneys, blood sugar and electrolytes from one blood draw.
- Slovenian labs often report enzymes such as GGT and CK in µkat/L, not U/L. Multiply µkat/L by 60 to get U/L.
- Standard CRP (infection) and hs-CRP (heart risk) are different tests with different cut-offs.
- One value just outside the range rarely means an urgent problem. The pattern and the trend matter more.
This guide explains the letters in front of test names on a Central European lab report, the units that confuse people, and the normal values for 13 common blood chemistry tests. Every range in the table names its source. It adds depth to our reference values table.
What does S- mean on a lab report?
S- means the test was measured in serum, the clear liquid left after blood clots in the tube. Slovenian hospital labs name each test with a sample prefix. The Golnik clinic lab list (2025) shows "S-kalij" with the material "serum" and "P-glukoza" with the material "plasma".
The same substance can have a different reference range in serum, urine or whole blood. This is why the prefix matters when you compare two reports.
These are the prefixes we confirmed on official Slovenian lab test lists:
- S- serum: S-kreatinin, S-CRP, S-CK, S-sečnina (urea).
- P- plasma: P-glukoza, drawn into a tube with fluoride.
- K- whole blood (kri): K-trombociti, K-hemoglobin, K-MPV in the blood count.
- U- urine and dU- 24-hour urine: U-kalij, dU-kreatinin.
- Ka- arterial blood, used for blood gases and critical profiles.
- S,P- either serum or plasma, as in "S,P-glukoza" on the UKC Maribor list.
Some international guides list B- for whole blood. The Slovenian lists we opened use K- instead. We did not find a separate "f" prefix for fasting on these lists, so follow the preparation note from your lab.
Which tests are in a blood chemistry panel?
A blood chemistry panel measures substances in serum or plasma that show how your liver, kidneys and metabolism work. MedlinePlus lists 14 tests in a US comprehensive metabolic panel. They are glucose, calcium, sodium, potassium, bicarbonate, chloride, albumin, total protein, ALP, ALT, AST, bilirubin, BUN and creatinine.
Slovenian referrals rarely use the word "panel". Your doctor ticks single tests instead, so your report may show only some of them. GGT, CK and CRP are often added. The kidney estimate eGFR can appear as "oGF (CKD-EPI)" on a Slovenian report.
What are normal values for ALT, AST, GGT, CRP, CK, creatinine and glucose?
For adults in our database, ALT is normal up to 33 U/L, AST up to 35 U/L and GGT up to 40 U/L. Creatinine is normal up to 100 µmol/L (1.13 mg/dL). Fasting glucose is normal at 3.9–6.1 mmol/L (70–110 mg/dL). The table shows all 13 tests.
| Test (unit) | In range | Borderline or out of range | Source |
|---|---|---|---|
| ALT (U/L) | up to 33 | 33–50 borderline; above 50 high | IFCC C-RIDL |
| AST (U/L) | up to 35 | 35–50 borderline; above 50 high | IFCC C-RIDL |
| GGT (U/L) | up to 40 | 40–60 borderline; above 60 high | IFCC C-RIDL |
| ALP (U/L) | up to 120 | 120–150 borderline; above 150 high | Lab (method-dependent) |
| Bilirubin, total (µmol/L) | up to 21 (1.2 mg/dL) | 21–34 borderline; above 34 (2.0 mg/dL) high | Lab (method-dependent) |
| Creatinine (µmol/L) | up to 100 (1.13 mg/dL) | 100–120 borderline; above 120 (1.36 mg/dL) high | NORIP |
| eGFR (mL/min/1.73 m²) | 90 or more | 60–89 mildly reduced; below 60 reduced | KDIGO 2024 |
| Glucose, fasting (mmol/L) | 3.9–6.1 (70–110 mg/dL) | 3.0–3.9 or 6.1–7.0 borderline; below 3.0 (54 mg/dL) or 7.0 (126 mg/dL) and above out | Endocrine Society |
| hs-CRP (mg/L) | below 1 | 1–3 moderate; above 3 elevated | AHA/CDC |
| CK (U/L) | up to 308 | 308–1,000 raised; above 1,000 markedly raised | IFCC / lab (37 °C) |
| Urea (mmol/L) | 2.8–7.5 (BUN 8–21 mg/dL) | below 2.8 or above 7.5 out | NORIP |
| Potassium (mmol/L) | 3.5–5.1 | 3.0–3.5 or 5.1–6.0 borderline; below 3.0 or 6.0 and above out | UK Kidney Association |
| Sodium (mmol/L) | 135–145 | below 135 or above 145 out | ESE / ERA-EDTA / ESICM |
Source: bands from the Blood Lab 360 knowledge base, with the organization named in each row. The documents are IFCC C-RIDL 2010, NORIP 2004, KDIGO 2024, Endocrine Society 2009, AHA/CDC 2003, UK Kidney Association 2023 and ESE/ERA-EDTA/ESICM 2014. Reference ranges differ between labs, so the range printed on your report applies first.
The CK source gives different ranges by sex: about 39–308 U/L for men and 26–192 U/L for women. Potassium from 6.5 mmol/L up is a separate, severe band in our database.
Why does my lab show different numbers or µkat/L?
Your lab may use a different method, a different reference group or a different unit. Slovenian lab lists often give enzymes in µkat/L. The Golnik list (2025) gives S-gama-GT below 0.92 µkat/L for men and below 0.63 µkat/L for women.
The conversion is simple. One µkat/L equals 60 U/L, because one katal is one mole per second and one unit is one micromole per minute. So 0.92 µkat/L is about 55 U/L. Our GGT band starts to flag above 40 U/L.
- ALT, AST, GGT, ALP, CK: µkat/L × 60 = U/L.
- CK: Golnik gives below 2.85 µkat/L for men (about 171 U/L).
- Creatinine: Golnik gives 62–106 µmol/L for men and 44–80 µmol/L for women. Our single band flags above 100.
- Glucose: Golnik gives 4.1–6.1 mmol/L for both S-glukoza and P-glukoza. UKC Maribor (2017) gives 3.6–6.1 mmol/L.
Mixing up units is one of the most common reading errors we see. A GGT of 1.2 looks tiny, but 1.2 µkat/L is 72 U/L. Always read the unit before the number.
Is CRP the same as hs-CRP?
No. Both measure the same protein, but they answer different questions. MedlinePlus explains that standard CRP looks for inflammation, such as an infection. hs-CRP measures very small increases and is used to estimate heart disease risk.
Our knowledge base holds only hs-CRP. For standard CRP we give the numbers from the sources we opened. MedlinePlus calls 0.8–1.0 mg/dL (8–10 mg/L) or lower a healthy amount. The Slovenian lists from Golnik and UKC Maribor use below 5 mg/L for S-CRP.
A standard CRP of 4 mg/L can be normal on your report. The same number as hs-CRP falls in our "elevated" band above 3 mg/L. Read the test name, not only the number. Our hs-CRP and inflammation guide explains the heart-risk use.
Which patterns in blood chemistry results point to a cause?
A single chemistry value says less than a group read together. These are the combinations our app checks, based on the notes in our knowledge base:
- ALT higher than AST, GGT mildly up, triglycerides high: fits fatty liver. See ALT, AST and GGT.
- GGT high with ALT normal: often alcohol or bile duct irritation. GGT reacts strongly to alcohol.
- AST and CK both high, ALT normal: points to muscle, often after hard exercise, not the liver.
- ALP high with GGT high: points to the bile ducts. ALP high with GGT normal points to bone. See alkaline phosphatase.
- Bilirubin mildly high, other liver tests normal: often harmless Gilbert syndrome. See high bilirubin.
- Creatinine high, eGFR normal for age, lots of muscle: often muscle mass, not the kidneys. See eGFR and creatinine.
- Urea high with creatinine normal: often dehydration or a high-protein diet. See urea and BUN.
- Potassium mildly high, everything else normal: can be a sampling artifact from a clenched fist or a long tourniquet. A repeat is sensible. See potassium and sodium.
- Fasting glucose 6.1–6.9 mmol/L: the higher-risk band. HbA1c adds the 3-month picture. See blood sugar and HbA1c.
See a doctor the same day if potassium is below 3.0 mmol/L or 6.0 mmol/L and above. The same applies to sodium outside 135–145 mmol/L with confusion or headache, and to fasting glucose below 3.0 mmol/L. Seek urgent care for CK above 1,000 U/L with muscle pain or dark urine. Yellow skin or eyes with abnormal liver tests also need prompt care. An eGFR below 60 needs a planned visit with your doctor.
How Blood Lab 360 reads this
You upload your report, and the app reads the test names with or without the S-, P- or K- prefix. It checks the unit first. Where the source allows it, the app uses bands for your age and sex. Our database holds 26 such age and sex band sets across all markers.
The app reads markers in groups, like the patterns above, not one by one. Every band shows its source. For follow-up, our database suggests a repeat liver panel after about 16 weeks, glucose after 12 weeks, and kidney tests after 24 weeks. An abnormal kidney result is confirmed sooner, after about 2–4 weeks.
The app does not diagnose and does not replace your doctor. For a general guide to a flagged value, read a value outside the reference range.
Frequently asked questions
What does S- mean on a lab report?
S- means the test was done on serum. It is a sample prefix used on Slovenian lab reports. P- means plasma, K- whole blood and U- urine. The prefix does not change what the number means for you.
What are normal blood chemistry panel values?
For adults in our database: ALT up to 33 U/L, AST up to 35 U/L, GGT up to 40 U/L and creatinine up to 100 µmol/L (1.13 mg/dL). Fasting glucose is 3.9–6.1 mmol/L (70–110 mg/dL), sodium 135–145 and potassium 3.5–5.1 mmol/L. Your lab's range applies first.
How do I convert µkat/L to U/L?
Multiply by 60. For example, 0.5 µkat/L of ALT is 30 U/L. The conversion works for all enzymes, including AST, GGT, ALP and CK.
How are CMP blood test results explained?
Read the unit, then the range on your report, then the pattern. Liver tests are read together (ALT, AST, GGT, ALP, bilirubin). Kidney tests are read through eGFR. Glucose needs a fasting sample.
Is a CRP of 5 mg/L high?
For standard CRP, the Slovenian lab lists we opened use below 5 mg/L as the range, so 5 is at the edge. As hs-CRP, 5 mg/L is above our 3 mg/L cut-off. Repeat hs-CRP when you are well, after about 4–8 weeks.
Do I need to fast before blood chemistry tests?
MedlinePlus says you may need to fast for several hours. Fasting matters most for glucose. Follow the preparation note from your lab or your doctor.
