· 4 min read
Why two laboratories can disagree about the same blood
A result flagged high at one laboratory can sit inside the range at another. Here is why that happens, and why it is not a mistake.
Blog
Plain-language writing about laboratory results — what reference ranges are, what the flags mean, and how to get more out of the appointment afterwards.
· 3 min read
Questions worth taking to a results appointment
Appointments are short. A few prepared questions tend to get further than trying to remember everything on the spot.
· 3 min read
What the letters beside your results mean
H, L, HH, LL, asterisks and the word critical. A guide to the flags laboratories print, what triggers them, and what they are actually for.
· 3 min read
Why this tool makes you check every value
Reading numbers off a scanned report is the step most likely to go wrong. Here is why the slowest part of the process sits in the middle.
· 4 min read
How a blood sample becomes a number on a report
Most of what can go wrong with a laboratory result happens before the analyser sees it. A walk through the journey from the needle to the printout.
· 3 min read
Why the same result looks completely different in another country
A glucose of 5.5 and a glucose of 99 can describe the same blood. Units, conversion factors, and how to avoid comparing numbers that are not comparable.
· 3 min read
Fasting, timing and the things that actually change your results
Some tests are exquisitely sensitive to when the sample was taken. Others are not affected at all. Knowing which is which saves repeat appointments.
· 3 min read
Why one abnormal result usually gets repeated
A repeat test is not a sign that something was missed. It is often the fastest way to find out whether a number describes the person or the sample.
· 4 min read
How to read a full blood count
The most commonly ordered blood test, and the one with the most numbers on it. What each group of results describes and how they relate.
· 3 min read
Why a positive screening test is often not what people assume
Sensitivity, specificity, and the reason a test that is right 99 per cent of the time can still produce more false alarms than real findings.
· 3 min read
What eGFR actually estimates, and what it does not
The kidney number on most reports is a calculation, not a measurement. Understanding the equation explains most of its quirks.
· 3 min read
Reading a lipid panel without the folklore
Good cholesterol, bad cholesterol, and the fact that one of the numbers is usually not measured at all.
· 3 min read
Why thyroid testing starts with the pituitary
TSH is not made by the thyroid, which is exactly why it is the first test. How the feedback loop works and why borderline results are usually repeated.
· 4 min read
Iron studies, and the way inflammation hides the answer
Ferritin measures stored iron and also rises with inflammation. That double role is the single most important thing to know about iron testing.
· 4 min read
HbA1c: what a three-month average can and cannot show
One number summarising months of blood sugar is remarkably useful, and it hides two things worth knowing about.
· 3 min read
Liver tests: what each enzyme actually points at
A liver panel measures several different things, only some of which come mainly from the liver. The pattern between them is what carries the information.
· 3 min read
The electrolyte panel, and why sodium is really about water
Sodium, potassium, chloride, bicarbonate, urea and creatinine appear together on almost every panel. What each contributes and how they interact.
· 3 min read
Urine tests, and the limits of a dipstick
A urine dipstick is fast, cheap and useful, and it answers a narrower question than most people assume. What the pads detect and what has to follow.
· 3 min read
Vitamin tests, and what the number is actually tracking
Vitamin D, B12 and folate are among the most commonly requested add-on tests. Each measures something slightly different from what people assume.
· 3 min read
Keeping your own record of results, and why it is worth it
Health records fragment across providers, countries and systems. A personal record is often the only place a full history exists.