Catching everything going around, or taking twice as long as everyone else to shake it off, usually has a reason worth finding.

When You Keep Getting Sick

Vitamin D does real work in immune function and deficiency is everywhere. B12 is needed to make the white cells that fight infection. And undiagnosed diabetes weakens immune response and slows healing, which is sometimes how it gets spotted in the first place.

The other thing worth separating out is background inflammation. When infections keep recurring, knowing whether something's actively going on right now versus a low-grade process ticking along changes what happens next. That's what the inflammatory markers are for.

Who Should Consider These Tests

• You catch things more often than people around you

• Illnesses take longer than they should to clear

• Recurring fever with no obvious source

• Cuts heal slowly, or you get mouth ulcers a lot

• You feel run down even between illnesses

• You've just finished repeated courses of antibiotics

What Each Test Tells You

This page lists 7 options. Here's what each one actually measures, so you can pick instead of guessing.

Blood tests

• Serum Magnesium Test: Magnesium keeps muscles and nerves behaving. Low levels show up as cramps, twitching eyelids and general fatigue.

• Widal Test: Screens for typhoid. If a fever's dragged past a few days here, this is usually one of the first things checked.

• Complete Blood Picture (CBP): Counts your red cells, white cells and platelets. It's the cheapest way to catch anaemia or an infection you didn't know you had, and it's the single most booked test we do.

• CRP test: Tells you there's inflammation somewhere. It won't tell you where, but it answers whether something's actually going on.

• hs-CRP Test: The sensitive version of CRP. Picks up the low-grade inflammation that matters for heart risk, which the standard test misses.

• Vitamin B12 Test: Your nerves and red blood cells need B12. If you're vegetarian, you're at real risk, and the symptoms are easy to miss: tingling hands, fuzzy thinking, no energy.

• Vitamin D (25 - Hydroxy Vitamin D, Serum): Your body makes this from sunlight, and most people who work indoors don't get enough. Low levels show up as aching bones, weak muscles and flat mood.

How to Prepare

• No fasting: CRP test, Complete Blood Picture (CBP), Serum Magnesium Test, Vitamin D (25 - Hydroxy Vitamin D, Serum), hs-CRP Test

• No fasting. Ask your doctor before pausing supplements: Vitamin B12 Test

• No fasting. Tell them the day your fever started: Widal Test

Tell the collection team everything you're taking, prescription or not. Plenty of supplements move these numbers, and without that context your report reads wrong.

How Often to Repeat

Test during or just after a run of illness rather than waiting for a good spell. Retest once any deficiency is being treated.

Understanding Your Results

Note when the last illness started. Several infection tests only go positive after a few days, so that date changes how a negative result should be read.

These tests point at a diagnosis. They don't make one. Read your report with a doctor who knows your history and what you're currently taking.